White mulberry (Morus alba)

Datasheet

Description

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White mulberry (Morus alba), compound leaves

Silkworm feeding on white mulberry (Morus alba) leaves

Common names

White mulberry, russian mulberry, silkworm mulberry [English]; gewone moerbei, witmoerbei [Afrikaans]; mûrier blanc [French]; weißer Maulbeerbaum [German]; iboberi [Kinyarwanda]; vitt mullbär [Swedish]; amoreira-branca [Portuguese]; mora, moral blanco, morera blanca [Spanish]; puting moras [Tagalog]; beyaz dut [Turkish]; dâu tằm, dâu tàu, tằm tang [Vietnamese]; murbei [Bahasa indonesia]; bebesaran [Malay]; توت أبيض [Arabic]; 白桑 [Chinese]; توت سفید [Farsi]; תות לבן [Hebrew]; शहतूत [Hindi]; 뽕나무 [Korean]; ログワ(kuwa) [Japanese]; Шелковица белая [Russian]

Species

Morus alba L. [Moraceae]

Synonyms

Morus alba f. tatarica Ser., Morus alba var. constantinopolitana Loudon, Morus alba var. multicaulis (Perr.) Loudon, Morus indica L., Morus multicaulis Perr.

Related feed(s)

Description

White mulberry (Morus alba L.) is a high-yielding pantropical and subtropical medium-sized tree. While it is traditionally used as fodder for silkworms, white mulberry provides a highly palatable forage suitable for most farm animals (Martin et al., 2017).

Description

Morus alba is a fast growing, deciduous, medium-sized tree that grows to a height of 25-35 m. It has a dense spreading crown, generally wider than the height of the tree. White mulberry can have a pyramidal shape or have a drooping habit. Its bole is straight, cylindrical without buttresses and up to 1.8 m in girth. The bark is vertically fissured, dark greyish-brown in colour, exuding a white or yellowish latex. The leaves are light green in colour, alternate, petiolate, cordate at their base and very variable in shape. They can be simple or compound (3-5 lobed) even on the same tree, dentate, palmately veined, coriaceous and caducous. The inflorescence is axillary and pendulous. The flowers are unisexual inconspicuous, greenish in colour, looking like catkins (male flowers) or spikes (female flowers). The trees are monoecious or dioecious without buttresses (Orwa et al., 2009). The fruit is a 5 cm long fleshy, juicy, edible but not very tasty berry that consists in a syncarp of achenes enclosed in succulent sepals. The seeds are very small and the 1000-seed weight is 2.2-2.3 g (Ecocrop, 2019; Orwa et al., 2009; Alonzo, 1999). It is thought that the genus name Morus comes from the latin word "mora" which could have referred to the late expansion of the buds. A celtic etymology "mor" has been proposed according to the colour of the fruit in the genus. The binomial taxon Morus alba may have been chosen after the light-coloured buds and not after the colour of the fruits (Orwa et al., 2009).

Uses

White mulberry is chiefly used to rear silkworm for silk production. Its foliage can be used as a source of fodder for livestock. The leaves and stems can be cooked as a vegetable. The fruits are edible and can be eaten raw or dried and used as a raisin substitutes. The fruits can be made into juice and beverages. In India, the fruits are traditionally used for dyeing wool in red or purple colour. The bark and wood have been used for centuries for tannery and paper fabrication. The white mulberry provides several environmental services (see below) and is used as an ornamental, in gardens and along roadsides and avenues. Many parts of white mulberry are used in ethnomedicine (Ecocrop, 2019; Orwa et al., 2009; Alonzo, 1999).

In China, mulberry trees are part of a millenial circular economy system including the mulberry trees, silk production, fish farming, agriculture and livestock farming: the silkworms feed on the leaves and the silkworm pupae are fed to fish. The silkworm faeces and the wastewater from silk processing are used to fertilize fish ponds while pond silt makes a good fertilizer for fodder crops that, in turn, are fed to livestock (Cook et al., 2005).

Distribution

White mulberry originated from China where it was already cultivated 4700 years ago. It was introduced to Europe during the 12^th century. It was introduced by the Spaniards in Latin America (Mexico, Peru) shortly after the conquest (Hanelt et al., 2001). White mulberry has been introduced to Australia where it became naturalized and is now considered a weed in New South Wales and Queensland (Queensland Government, 2011). The main area of cultivation of white mulberry tree are in the Middle East, East Asia and South East Asia. Prior to the invention of synthetic silk, the mulberry was cultivated in Europe and America for this silk production.

Morus alba is a very adaptable species that is widely found from the tropics to the temperate regions (even sub-arctic) and from sea level to altitudes as high as 4000 m (Ercisli et al., 2007). In the wild, the trees grow in ravines, valleys and coastal areas (Orwa et al., 2009). White mulberry can be cultivated where daily temperatures range between 18 to 30°C and annual rainfall is between 600 to 2500 mm with relative humidity between 65 to 80% (Ting-Zing et al., 1988). The trees are tolerant of shade but are highly susceptible to drought. They can grow on a variety of soils from sandy loam to clayey loam but prefer deep, well-drained alluvial loamy, neutral to slightly acidic soils (pH from 6 to 7.5) (Ecocrop, 2019). Morus alba is tolerant of poor soils and can be used to reclame soils contaminated by heavy metals (Zhou et al., 2015; Alonzo, 1999).

Processes

Drying

Drying white mulberry leaves can be done under sunlight or under shade. Drying under the sun needs 3 to 5 days while drying under the shade needs about 5 days even during the rainy season in the tropics: temperature 25-32°C and humidity of 80-90% (Nieves et al., 2008a; Montejo-Sierra et al., 2018). Though sun drying seems to be quicker and therefore more interesting, drying in the shade (in a dry place protected from rains) is in practice more advisable because leaf production and harvest are maximal during the rainy season. In addition, sun drying is difficult during the rainy season (extra work necessary by some unexpected rain fall) and not secure, with potential mycotoxins development (Montejo-Sierra et al., 2018). The nutritive value appears to be higher in white mulberry foliage dried under shade (Montejo-Sierra et al., 2018).

Leaf meal preparation for poultry

The preparation of white mulberry leaf meal for poultry is done as follows: the foliage is cut after 60-70 days of regrowth at 50 cm above soil and then dried during 5-7 days under sunlight so that DM reaches 75-80%. The coarser stems are then removed and the remaining is ground with a hammer mill to a size particle of 3 mm (-1 mm) (Bustamante, 2008; Casamachin et al., 2007).

Silage

Mulberry foliage can be harvested for silage. In Vietnam, white mulberry silage was obtained by chopped foliage to 2-3 cm long, wilting it under sunshine, adding 5% rice bran and 5 % molasses, and then putting the mixture in plastic bags stored at room temperature during 56 days. The resulting silage had a high protein and ash content and had the best quality low pH, low N-NH3 ratio) with molasses addition (Nguyen Xuan Ba et al., 2005). In Cuban, white mulberry foliage was ensiled with Guinea grass (Megathyrsus maximus), the optimal proportion being 70:30 mulberry/Guinea grass for fermentation process (Ojeda et al., 2006).

Forage management

Leaf yield

Fresh leaf yield is very variable and depends on the age of the trees and more specifically on the diameter of the trunk: fresh leaf yield ranged from 6.5 to 33.5 t/ha in Spain between the first and the 7th year of growth. In France, 17 t/ha were reported and it was 20 t/ha in Paraguay in a 4-year old plantation harvested at 30 cm from the ground (Benavides, 2000). In Cuba, DM forage yield as high as 10 and 12 t/ha/year were reported (Martin et al., 2014). In Uganda, DM leaf yield was near 19 t/ha/year for foliage cut at 2 or 6 months intervals. The nutritive value was the highest at short cutting intervals (Kabi et al., 2008).

Cultivation

Mulberry trees be propagated by seed and by cuttings, grafting and air-layering (Alonzo, 1999). In India, white mulberry seeds are sown in nurseries. Provided thay have been scarified, the seeds germinate within 9-14 days and the seedlings are pricked out when 10-15 cm tall. Prior transplantation of the seedlings (which should occur during the cold season or at the beginning of the rains) the terminal leaves are stripped (cut) (Alonzo, 1999).

Vegetative propagation is generally done with cuttings of 3-4 buds for the production of leaves to feed silkworms. The cuttings are buried for 15-20 cm of their length, including 2 buds. After two months, the rooted cuttings are ready to be planted out in the field. Mulberry trees are planted in a way that eases leaf harvest and pruning. Density of plantation is thus very variable and depends upon the intensity of pruning that can be allowed. 30,000 plants/ha will be adequate for low pruning operations, 7,000-12,000 plants/ha for medium pruning, and 2,250-6,000 plants/ha for high pruning intensity (Benavides, 2000). In India, cuttings planted in paired rows have the following spacing: 1.8 m between pairs, 0.6 m within a pair and 0.5 within the row (Alonzo, 1999). After plantation, the field requires occasional weeding (Alonzo, 1999).

Grafting mulberry trees was reported to yield higher amount of leaves, therefore resulting in silkworm cocoons of higher grade (Alonzo, 1999). After establishment the trees should be pruned from time to time to allow the growth of new shoots. They should be protected against fire and browsing. The young trees grow quickly (4.5 m in the first 2 years) and coppice readily (Orwa et al., 2009). Morus alba begins to bear in the first or second year of cultivation (Ecocrop, 2019).

White mulberry trees could be planted in association with tropical grasses (jaragua, brachiaria brizantha or kikuyu) or with legumes like subterranean clover (Estrada et al., 1998; Talamucci et al., 1993).

Harvest and storage

Leaves harvested for feeding silkworms are stored in loose heaps in cool rooms. Heating, fermentation and drying-out are prevented (Alonzo, 1999).

Grazing and browsing

In Italy, white mulberry trees have been traditionally planted for combined silvopastoral systems where both cattle and sheep could browse on their higher and lower branches (Talamucci et al., 2000). In Cuba, the survival of trees intented for browsing was better if the trees were sufficiently spaced (over 2- 3 m). The height of cutting was important for tree survival and it was suggested that the stand of white mulberry should not be overgrazed so that height remains above 1 m high (Medina et al., 2004).

Environmental impact

Climate smart use

In Italy, white mulberry trees planted in association with grasses or legumes and grazed by both cattle and sheep were found to be suited for optimal availability of fodder during hot and dry summers (Talamucci et al., 2000).

Soil erosion and soil improver and reclamation

White mulberry trees are reported to be useful for stabilizing physical soil-conservation structures while leaf-fall provides organic matter to the soil and reduce soil temperature in hot areas. White mulberry could be used to remove lead from lead-contaminated soil (Zhou et al., 2015; Orwa et al., 2009).

Shade or shelter

Mulberry trees can be planted for sheltering orchards from wind (Orwa et al., 2009).

Weed

In South Eastern Queensland (Australia), white mulberry is ranked among the top 200 most invasive plants of watercourses (riparian areas), native bushland, forest margins and roadsides (Queensland Government, 2011).

Nutritional aspects

Nutritional attributes

White mulberry foliage has a relatively high protein contents (avegage 19% DM, ranging from 11 to 26% DM). It has a high mineral content (up to > 20% DM) and thus a higher macromineral content than foliages from other trees. In particular, the leaves accumulate calcium (1.4-3.6 % DM). The plant has good vitamin content mainly from C (ascorbic acid, 0.3% DM) and B (nicotinic and pantothenic acids, riboflavin) groups (Martin et al., 2017).

Ruminants

White mulberry is a high yielding forage tree whose foliage has high nutritive value for ruminants (Martin et al., 2017).

Digestibility and nutritive value

The digestibility and degradability of white mulberry forage are high, though, like other forages, its nutritive value is higher at early stage of maturity/regrowth after cutting, and during the wet season. In vitro digestibility of white mulberry leaves is very high (>80%) (Martin et al., 2017; Martin et al., 2014). Degradation rates in goats after 48h were very high: 93% for DM, 97% for protein and 85% for NDF (Schmidek et al., 2002). In sheep, it was shown that even low levels of white mulberry leaves increased significantly diet degradability (Salinas-Chavira et al., 2011).

Those rates also depend on leaf maturity: young leaves are twice more degradable than mature ones (Schmidek et al., 2002). In Uganda, rumen degradable protein of white mulberry in steers was high (10-20% DM) but decreased with maturity. Optimal nutrient degradability was obtained with cutting intervals of 1 to 2 months (Kabi et al., 2008). Such result had been observed earlier: the concentration of total digestible nutrients (TDN) was about 56% after 70 days of regrowth, then slightly decreasing at further stages (84, 98 and 112 days). The digestible energy of 10.6 MJ/ kg DM went down to 9.8 MJ/ kg after 112 days and the net energy for lactation went from 5.1 MJ/kg (70 days) to 4.6 MJ/kg (112 days) (Boschini-Figueroa et al., 2006).

The nutritional value of white mulberry leaves may vary with the season of harvest: in Ethiopia, the in vitro DM digestibility and N digestibility were higher when white mulberry was harvested during the wet season. This should be taken into accont for optimal forage management (Assen Ibrahim et al., 2016).

Jersey cattle offered white mulberry foliage (84 days of regrowth), black sorghum forage (77-day old) or a mixture of both forages had higher DM intake on white mulberry foliage than on the other two diets, though intake was slightly lower than expected Boschini, 2000).

When white mulberry foliage was used to replace 33%, 67% or 100 % King grass (Pennisetum purpureum x Pennisetum typhoides) in a mixture of tropical grasses (jaragua (Hyparrhenia ruffa), kikuyu (Pennisetum clandestinum) and brizantha (Brachiaria brizantha), increasing level of white mulberry leaves in the diet improved the overall degradability of the DM in the ration as white mulberry leaves had a higher degradability than the grasses (Estrada et al., 1998).

Dairy cows

White mulberry leaves included at 0.1 or 0.2% BW (DM basis) of Cuban crossbred dairy cows (444 kg) with medium milk production increased milk production by 0.56 kg (8.6%) and 2.12 kg (32.3%), respectively (Casanovas et al., 2004). The increasing level of white mulberry resulted in better balance of the diet (containing Cynodon nlemfuensis and king grass Pennisetum purpureum cv. King grass, final molasses, urea and mineral salt). Medium yielding (8-10 kg milk/day) crossbred (Holstein x zebu) cows fed on king grass and supplemented with white mulberry and Leucaena leucocephala foliages had access to increased DM and had higher milk yield (Lamela et al., 2010). Such improvements in milk yield could not be obtained with high-yielding cows (Hernandez et al., 1999 cited by Casanovas et al., 2004).

In Columbia, dairy cows grazing kikuyu grass (Pennisetum clandestinum) and supplemented with a concentrate received either 30% white mulberry leaves (DM basis) or 25 % black elder (Sambucus nigra) leaves (DM basis) so as to have isoproteic diets. Cows receiving white mulberry yielded 12.6 kg milk vs 12.3 kg for cows receiving black elder and 10.9 kg for the control. Milk quality parameters were 3.14 %, 2.72 %, and 11.19 % for white mulberry and 3.24 %, 2.84 % and 11.56 % for black elder, being lower than those of control (3.52 %, 2.97 % y 11.73 %). During the experimental period all cows lose weight (Saavedra-Montañez et al., 2018).

In Cuba, it was possible to replace up to 60% concentrate with fresh mulberry in dairy cattle rations without altering feed intake or production performance (Boschini, 2003).

Growing cattle and beef cattle

Heifers and steers

In Costa Rica, young weaned dairy heifers grazing on Cynodon nlemfuensis were offered white mulberry leaves ad libitum and concentrate (0.5; 1 or 1.5 kg/day). Their maximal feed intake was 1.8% BW. The better feed conversion ration was obtained with 1 kg concentrate. Heifers could reach 120 kg BW in 5.5 months (Jiménez et al., 1998). Similar positive effects were observed in Cuba with young (70 kg) grazing Holstein x zebu steers supplemented daily with 6 kg chopped white mulberry foliage and 0.5 kg concentrate. They had higher daily gain (600 g/day) than young steers receiving 1 kg concentrate and pangola hay ad libitum. They had lower fecal egg count of gastrointestinal nematodes. It was concluded that white mulberry had positive effect on both production performance and health parameters (Soca et al., 2010).

In Vietnam, local crossbred bulls (184 kg) were offered 5, 10 or 15% (dietary DM basis) white mulberry leaves to partially replace cotton seeds in their rations during 84 days. No differences in overall feed intake or average daily gain could be observed at any level of white mulberry leaves inclusion. However, protein and ME intakes were significantly decreased when inclusion of mulberry leaves went from 5% to 15% and the feed conversion ratio (feed/gain) was improved by the utilization of white mulberry leaves (Vu et al., 2011).

Fattening cows

In Costa Rica, it was possible to make good quality silage with white mulberry foliage with mostly lactic acid fermentation and therefore good preservation properties. The white mulberry silage was of higher quality than other grass silages and it was possible to obtain better weight gains in fattening cows in spite of a lower voluntary feed intake than expected (Gonzalez et al., 1996).

Meat quality

In South Korea, white mulberry silage offered as sole supplementation of a total mixed ration to fattening Hanwoo steers did not result in difference in health parameters, but increased the fat and free amino acids content and reduced the protein content in longissimus dorsi (Jeon et al., 2012). Some components of white mulberry silage like 1-deoxynojirimycin (1-DNJ) are antioxidant. Adding white mulberry silage to the diet of Hanwoo steers could scavenge up to 50% alkyl radicals even at very low level of inclusion (0.125 mg/ml of 1-DNJ)(Jeon et al., 2009).

Sheep

In Ethiopia, white mulberry leaf meal could be used to completely replace concentrate (noug seed cake and wheat bran at ratio of 1:2) in Tigray highland male lambs (17.8 kg) without having deleterious effect on DM, OM, NDF and ADF intake or on lambs weight gain, slaughter weight or carcass weight (Tesfay et al., 2018).

In China, white mulberry leaves (240 g/kg) were successfully used to replace rapeseed meal as a supplement to an ammoniated rice straw-based diet for growing lambs. Adding white mulberry leaves slightly increased rice straw intake but only the total replacement of rapeseed meal yielded similar growth performance in lambs. The feed conversion ratio (feed: gain) was better for rapeseed meal than for white mulberry leaves and the overall lamb growth remained relatively low in all cases. The feed costs were slightly decreased by the replacement of rapeseed meal (Liu et al., 2000)

In Puerto Rico, chopped whole plant forage of white mulberry could be used to supplement young lambs grazing Guinea grass (Megathyrsus maximus) and it resulted in higher energy provision than other foliage (Hibiscus rosa-sinensis) or Guinea grass. However, no significant differences could be observed in growth parameters of the animals (Ramos-Santana et al., 2010).

In Mexico, in spite of their phytooestrogenic component, white mulberry leaves could be fed at up to 60% (DM dietary level) to 107-day old Pelibuey lambs during a 40-60 day period without delaying the onset of puberty (Aguilar-Urquizo et al., 2013).

In India, chopped white mulberry leaves were offered in mixture (33% or 50%) with chopped sorghum straw and concentrate (250 g and 100g respectively) to pregnant ewes (22-23 kg). It resulted in similar DM intake, and digestibilities of nutrients except for fat which was reduced. Protein requirements of ewes were met but not for total digestible nutrients. Feeding white mulberry leavs had no effect on birth weight of lambs (Prasad et al., 1995).

In India, the digestible protein and ME values of fresh white mulberry leaves were lower for sheep than for goats. The average daily gain of lambs was 30.8 g (Kantwa et al., 2006). These results were not consistent with previous observation where DM intake (3.55% BW, 146% of their requirements), protein and crude fibre digestibilities, Ca and P balance were higher in sheep than in goats (Prasad et al., 1991).

Goats

In India, fresh leaves of white mulberry fed to goats resulted in an average daily gain of 42.4 g which was higher than that of sheep (Kantwa et al., 2006). These results were explained by a lower mean retention time in the rumen of goats than in the rumen of sheep, both values being related to better feed utilization and feeding level (higher intake and better crude fibre digestibility in goats) (Kantwa et al., 2008). In a prior experiment, DM intake had been reported to be 2.74% BW, supporting only 78% of goats requirements while protein and crude fibre digestibilities, Ca and P balance were lower in goats than in sheep (Prasad et al., 1991).

In Tanzania, white mulberry dry leaves mixed with maize bran at 50:50, or fresh leaves of mulberry alone, or dry leaves of mulberry alone, or whole branches of mulberry were fed to goats. The higher DM intake (51.7 g/kg^0.75) and DM digestibility (66%) were observed in goats fed on fresh mulberry leaves. The highest daily gain (92 g/d) was observed in goats receiving fresh white mulberry leaves as the sole feed. Results obtained with dry leaves and branches were not much lower (Omar et al., 1999).

The variety of white mulberry and age of regrowth could affect digestibility (the younger foliage being more digestible): in Brazil, varieties FM 86 and FM SM were found to have good in vivo digestibility parameters in goats feeding and to be able to support goats growth (Dorigan et al., 2004).

In Costa Rica, fresh or partially dehydrated mulberry leaves were offered to goats in a comparison with fresh of partially dehydrated star grass (Cynodon nlemfuensis). DM intake was higher for white mulberry in both forms and represented more than 3% BW. Protein intake was more than twice higher with white mulberrry than with star grass, but digestibility parameters were not significantly different (Rodriguez-Zamora et al., 2012).

When chopped white mulberry foliage (leaves and twigs) was compared to ramie (Boehmeria nivea) or black sorghum, its DM intake was 1.94%BW vs 0.97% BW for ramie and 0.90% BW for black sorghum. Protein intake from white mulberry and ramie were found to be high enough to support maintenance requirement and to get an average daily gain of 50 g/day. The diet containing white mulberry foliage yielded the higher fresh forage intake, dry forage intake and protein and NDF intake (Elizondo-Salazar, 2004).

In Puerto Rico, newly weaned Nubian goats fed on pangola grass (Digitaria eriantha) received either dry mulberry leaves at 4% BW, either concentrate at 0.6 kg/d/head during the first 3 month and 0.8 kg/d/head in the last 3 ones. Dry mulberry leaves could replace concentrate in pangola based diet for goats (Ramos-Santana et al., 2014).

In India, it was possible to feed goats on tree forage mixtures containing Leucaena leucocephala, white mulberry and neem (Azadirachta indica) in 2: 1: 1 ratio, in order to replace soybean meal in a wheat straw-based diet offered ad libitum during 2 months. DM intake and nutrient digestibility were unchanged. N balance was positive and comparable in both diets, the digestible crude protein and TDN (total digestible nutrients) were also comparable and health parameters were not different when goats were fed on the mixture of tree forages or on soybean meal (Patra et al., 2002). A further experiment showed that the same forage tree mixture could support the requirement of pregnant goats and contribute 36% of the total DM intake without affecting animal health or reproductive performance (Patra et al., 2003). A similar experiment reported that tree forage mixture of Leucaena leucocephala, white mulberry and Tectona grandis in the same ratio and offered during 4 months to goats fed on a wheat straw-diet had no adverse effect on voluntary intake, nutrient utilization, serum enzymes and immune status (Anbarasu et al., 2004).

In Costa Rica, kids (3 month old, 10.2 kg) fed on Guinea grass and dehydrated citrus husks could be supplemented with white mulberry foliage at 0.5% BW; 1.5% BW or 2.5% BW. Their feed intake was the highest at the level of 1.5% BW. Best performance was obtained at the two highest inclusion rates (Gonzalez et al., 2001).

Silage

In Vietnam, growing goats (17.3 kg) could receive 250 g/day, 500 g/day, 750 g/day or ad libitum white mulberry silage. The highest DM intake was 3.41% BW and it was obtained when the level of white mulberry silage was 750 g/day (40% DM dietary level) as a supplement to natural grass. When the silage was fed alone, the DM intake was 3.02% BW. DM and OM digestibilities were not different among treatments but there was an increasing N retention with increasing silage level: on 100% white mulberry silage, the N retention was 3 times higher than on natural grass (Nguyen Xuan Ba et al., 2005).

Pigs

The use of Morus alba leaves in pig feeding was almost unknown before the end of the 20th century (Chiv Phiny et al., 2003). Since then, numerous experiments described mulberry foliage as a valuable source of protein for pigs that could partially replace soybean meal. It was shown that N digestibility of mulberry leaves was high in pigs (84%) and that N retention was about 65% of the N ingested (Ly et al., 2001). Its relatively high fibre content might however be a limiting factor in pig feeding.

Growing and fattening pigs

In Cambodia, white mulberry leaves included at 30% dietary level (DM basis) and compared to leaves of Tricanthera gigantea were reported to have higher in vitro digestibilities and in vivo DM, OM and N digestibilities (Ly et al., 2001). It was suggested that mulberry leaves could be supplemented with dried freshwater fish in order to provide enough methionine to the pigs since mulberry were reported to be deficient in sulphur amino acids (Ly et al., 2001). In another experiment, mulberry leaves were fed to young growing pigs (14.2 kg mean body weight) at increasing levels : 0%, 15%; 30%, and 50% DM basis) in order to study digestibility indices and N balance in a rice-based diet. Pigs fed on the highest level (50%) of mulberry leaf had lower intake than pigs fed up to 30% mulberry foliage. DM and OM digestibilities were not significantly affected by mulberry leaf inclusion while N balance and N retention increased with mulberry leaf level in the diet. DM, OM and N digestibilities and N balance had a tendency to be higher with fresh leaves, even at 45% of the daily intake of animals, than with leaf meal. It was concluded that mulberry leaves could be fed as the main protein source to growing pigs (Chiv Phiny et al., 2003).

In South America, fattening pigs could be fed on 15% to 24% mulberry leaf meal and have similar slaughtering weight than pigs finished on conventional diet (Araque et al., 2005; Trigueros et al., 1997). In Venezuela, mulberry leaf meal was assessed as a source of protein for fattening pigs fed on sugarcane juice. This combination was suggested since sugarcane juice is high in energy but very low in both protein and fibre, two element provided by mulberry leaf meal. This experiment concluded that at 8% or 16% dietary inclusion, mulberry leaf meal allowed to replace 89-92% of conventional feed. Animal growth was better at 8% inclusion (Gonzalez et al., 2006). In Cuba, 27-30% of total dietary protein from a commercial diet could be replaced by fresh mulberry leaves in fattening pigs with similar animal performance and a better feed: gain ratio over the whole fattening period (Contino et al., 2008d). At 20% dietary inclusion, mulberry leaf meal increased feed intake of fattening pigs without modifying feed conversion ratio. The pigs had lower backfat and ham weight while meat quality was not affected (Pérez et al., 2017).

Sows

In Mexico, gestating sows could be successfully fed on commercial diet with fresh white mulberry foliage. The inclusion of chopped foliage increased sows intake. It was possible to replace 25% of the commercial diet with mulberry leaves though the highest results were found when the control commercial diet was added mulberry fresh foliage (Muñoz, 2004). In Cuba, gestating sows fed ad libitum on mulberry foliage had higher hemoglobine content, better intestinal tissues (increased number of villosities in the intestine) and larger digestive organs than sows fed on commercial diet (Contino et al., 2008c). Gestating sows fed on mulberry leaves ad libitum had similar intake to those fed on commercial diet and their growth and reproductive performance were enhanced: higher number of piglets alive 48h after birth, higher average weight of the litter, higher viability percentage and reduced diarrhoea percentage in the offsprings (Contino et al., 2008a; Contino et al., 2008b).

Mulberry leaf polysaccharides

Piglets

Polysaccharides extracted from white mulberry leaves have been found to result in better health status in weanling piglets. They were shown to be more efficient than control diet or antibiotics for several parameters like daily feed intake, feed/gain ratio, diarrhoeal incidence (lower), blood glucose, and gut health (lower E. coli, higher lactobacilli and bifidobacteria) (Zhao et al., 2015)

Mulberry in pig feeding (Cuba) (in Spanish)

Poultry

Poultry can be fed white mulberry leaf meal. Inclusion levels commonly studied varied from 3 to 9% in laying hens and 4 to 12% in broilers. In free range chickens higher levels ranging from 10 to 30% were investigated. White mulberry leaf meal is a bulky, fibrous product, which may limit its use in poultry as it hampers animal intake and digestibility, and increases passage rate in the digestive tract and yield liquid faeces. Poultry has to get used to this feed through an adaptation period (Ly et al., 2017).

Digestibility and nutritive value

DM digestibility of a high-quality mulberry leaf meal (protein 30% DM) was relatively low (37 and 35% respectively) while protein digestibility was high (73 and 72%). AMEn values were also high: 7.62 MJ/kg in hens and 7.52 MJ/kg in broilers (Al-Kirshi et al., 2013). The use of mulberry leaf meal in poultry diet was reported to increase total gastro-intestinal tract weight (including gizzard and caeca) and could be related to an increased digestive activity with inclusion level as low as 10%. Though no difference in pancreas and liver weights was observed, some steatosis and multiple focal necroses were observed in liver of broilers fed on 30% mulberry leaf meal (Dorigan et al., 2011).

Broilers

In broilers, several experiments with increasing levels of mulberry leaves indicated that inclusion rates from 12 to 30% had deleterious effects on animal growth, on feed conversion ratio (Herrera et al., 2014; Olmo et al., 2012; Dorigan et al., 2011; Herrera et al., 2009; Bustamante, 2008; Casamachin et al., 2007). However no mortality of morbidity increase was shown at these levels.

In naked neck fowls, it was possible to include mulberry leaf meal at 3% dietary level without affecting animal performance and meat quality in comparison to the control diet. Skin pigmentation was enhanced by inclusion of mulberry (Herrera et al., 2014).

Laying hens

In laying hens, inclusion of mulberry leaves at 9% dietary level had no effect on egg production when compared to a traditional diet (Suda, 1999).

Quails

In quails, it was possible to have better laying percentage from quails fed on 15% white mulberry leaf rather than on control diet. However, a higher level of 20% was deletarious to egg production (Bermudez et al., 2013 cited by Ly et al., 2017). A later experiment found that 10% white mulberry leaves decreased laying percentage in quails while the feed consumption and egg weight were not affected (Hermana et al., 2014).

The susceptibility of poultry to the change in diet could be attributed to the fact that commercial lines had been bred for rapid growth on optimal diet (Ly et al., 2017). From the results reported above, it can be concluded that optimal level of white mulberry in diet should be about 10% in broilers, in quails and laying hens.

Rabbits

Fresh leaves

Fresh white mulberry leaves are well accepted as forage by growing rabbits or by adults, in reproduction or not. This has been demonstrated in different trials: in Mozambique (Mc Nitt et al., 1980; Timberlake et al., 1985), in Nigeria (Bamikole et al., 2005), in India (Deshmukh et al., 1989; Rohilla et al., 2000), in Vietnam (Nguyen Quang Suc et al., 2000; Viet, 2006), in Cuba (López et al., 2004), in Venezuela or in Mexico (Ramos-Canché et al., 2011; Nieves et al., 2004).

Used as sole feed, fresh mulberry leaves allow maintenance of adult rabbits (Deshmukh et al., 1989) or an acceptable growth rate for fattening rabbits : about 40% the growth rate of rabbits fed a balanced diet (Bamikole et al., 2005). However, if used as sole feed for rabbit does, fresh leaves are not able to provide a normal reproduction (López et al., 2012).

Proposed ad libitum in addition to a concentrate, fresh (or just wilted) mulberry leaves may represent 30-40% and even up to 60% of the total DM intake without significant perturbation of growth of rabbits for Angora wool production. Technical or economical advantages depend mainly of the type and quantity of concentrate chosen in the study. Generally, no significant perturbation was observed for carcass traits or physiological parameters obtained even with a high proportion of leaves (Premalatha et al., 2012; Ramos-Canché et al., 2011; Bhatt et al., 2010; Rohilla et al., 2000; Nguyen Quang Suc et al., 2000; Mc Nitt et al., 1980).

For rabbit does, lower reproduction traits were observed with white mulberry leaves distributed ad libitum in addition to a restricted commercial diet (60% of the control) than with the control itself or the distribution in the same conditions of Hibiscus rosa sinensis foliage: 5.6 kits born alive per litter vs 7.0 and 7.8 for the 2 other treatments (Garcia-Contreras et al., 2009). However, if white mulberry leaves are proposed together with other forages such as sugar cane stalks, and leaves of sweet potato or Neonotonia wightii forage in addition to a local concentrate, reproduction traits were considered as perfectly acceptable (López et al., 2011; López et al., 2004).

Dried leaves

White mulberry leaves dried in the sun or in the shade under a roof were succesfully used as a feed ingredient for growing meat rabbits or Angora rabbits by numerous authors (Bhatt et al., 2008; Dihigo et al., 2008; Hernandez et al., 2014; Ly et al., 2017; Martinez et al., 2005; Nieves, 2009). The most frequently acceptable proportion of dried mulberry leaves in a balanced experimental diet is 25-30% (Nieves et al., 2006; Prasad et al., 2003). In some experiments, inclusion rates of 60-75% and even 92% were possible without altering health, and with growth performance in relation with nutrients balance in the final diet (Mora-Valverde, 2012; Ramos-Canché et al., 2011; Ferreira et al., 2007).

Silage

Silage is not a commonly used for rabbit feeding (Lebas et al., 1996). However, a study was conducted during 12 weeks with growing rabbits receiving silage as sole feed. It was silage of imperial grass (Axonopus scoparius), or a silage made with 70% imperial grass + 30% meadow buttercup (Ranunculus acris), or 30% ramie (Boehmeria nivea) or 30% mulberry leaves (Morus alba); a control group received fresh imperial grass only. Growth rate of rabbits was similar (134 to 141 g/week) with the 3 silages containing 2 types of forages; those values were significantly higher than those obtained with imperial grass silage only (123 g/w) or fresh imperial grass (109 g/w)(Villa et al., 2016). This demonstrates that even with that presentation (silage), mulberry leaves mixed with an other forage are suitable to feed growing rabbits.

Nutritive value

White mulberry (Morus alba) leaves can be used to feed growing rabbits or Angora rabbits without particular restriction (provided the nutrient content of the daily ration is respected). White mulberry leaves are sometimes included as control in the study of other raw materials (Vázquez-Pedroso et al., 2016; Premalatha et al., 2012; Singh et al., 1984). For reproduction, some additional experiments would be welcome before unrestricted recommendation. Though only few experiments have been conducte,, the main problem seems more related to nutrient balance than to the presence of a particular substances, even if molecules with known pharmacological activities are numerous in mulberry leaves. This last point should however not be dismissed (Chan et al., 2016; Garcia-Contreras et al., 2009; López et al., 2004).

In the formulation of balanced diet, white mulberry leaves should be used as a forage with relatively moderate fibre content, high protein content(15-22% DM) and a high content of digestible energy : 11.4 MJ/kg DM on average, as shown in the table below. Proteins are highly digestible for a forage (73% on average), a value higher than that of alfalfa (60-65%). This protein are relatively rich in lysine (120% of requirements) but deficient in sulphur amino acids (86% requirements). In addition, mulberry leaves are very rich in calcium (twice recommended level) but deficient in phosphorus (Lebas, 2013).

Authors	Presentation	Method	% protein	Protein dig.	DE MJ/kg
Deshmukh et al., 1993	fresh	100%	22.1	74%	10.78
Prasad et al., 2003	dry	0-15-30-45%	15.3	70%	10.84 *
Bamikole et al., 2005	fresh	100%	23.1	84%	14.90 *
Nieves et al., 2006	dry	100%	18.0	65%	9.74
Ferreira et al., 2007	dry	91.19%	19.2	79%	11.90
Nieves et al., 2008b	dry	0-30%	19.3	66%	9.95
Average	-	-	19.5	73%	11.4

Other species

Silkworm (Bombyx mori Linnaeus, 1758)

The silkworm is a monophagous insect that feeds only on mulberry leaves and only during the 25 days of its the larval stage. Leaves of the white and black mulberry have been used for centuries as their unique feed. Many factors in the mulberry composition, and particularly the amino acid profile, the level of vitamins C and of vitamin of the B complex, may influence the health status of the larvae and the quality of the cocoon (Bhattacharyya et al., 2016). Silkworm feeding goes beyond the scope of Feedipedia and readers interested in that topic may consult specialized literature on silk production.

Nutritional tables

Tables of chemical composition and nutritional value

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used