Instead of corn silage for feeding lambs, scientists proposed mulberry leaves

Mulberry or mulberry is an environmentally resistant tree that is widely distributed in CHINA. Since the lack of high-quality feed endangers the development of the national sheep industry, the researchers advise considering mulberry as an alternative.

Experts from an international research group from China , Estonia and Australia (Henan International Joint Laboratory for Nutrition Regulation and Ecological Raising of Pets, College of Animal Science and Science, Henan Agricultural University; Institute of Veterinary Medicine and Animal Science of the Estonian University of Life Sciences; Institute sustainable policy at Curtin University, Australia).

“The shortage of high-quality roughage is an obstacle to effective livestock management in China. Canned feed is needed to feed livestock when pastures are not available. Ensiling the crop reduces nutrient loss compared to haymaking and is often used in livestock production.

However, the increasing population in China and the growth in the number of farm animals means that there is limited land available for cultivation for the production of conventional feed, such as corn silage. Therefore, alternative sources are needed.

The mulberry tree grows throughout China due to its unique drought tolerance, deep roots, and heat resistance. Virtually no watering required.

When harvested as animal feed, mulberry has a high dry matter productivity under a wide range of conditions, up to 20–30 t/ha/year when cut at 9–10 week intervals.

Mulberry trees are also recognized worldwide as an important crop for bioenergy and biofuel production.

Although corn for silage is estimated to be grown on 1.67 million hectares in China, it is quite a costly practice, with a short growing season a significant limiting factor in the north of the country.

While yields of 20–25 tdm/ha/yr are achievable, irrigation and high rates of nitrogen fertilization are often required. Maize's significant nitrogen fertilizer requirements contribute to carbon dioxide emissions from fertilizer production, and therefore large-scale cultivation of this crop plays an important role in global climate change.

Mulberry trees, in contrast, are considered important carbon dioxide sequestrants and are relatively undemanding to additional nitrogen, phosphorus and potassium fertilizers, although a good yield response to vermicompost has been reported.

Through the creation of multi-purpose cultivated varieties, mulberry has expanded its use over 5,000 years from medical supplements and cosmetics for humans to animal husbandry.

The nutritional value of mulberry leaves is high. The content of crude protein can reach 34% with a balanced amino acid composition. The leaves are low in fiber and rich in flavonoids, sterols, polysaccharides, alkaloids and other biologically active substances. So this is a high-quality protein feed resource with good prospects for use.

Mulberry leaves are better digested by goats and sheep, for example, than oat hay and alfalfa hay. Unfortunately, the nutritional value of fresh leaves is not easy to preserve for a long time, the quality decreases when dried.

Silage from mulberry leaves retains more nutrients while reducing the content of anti-nutritional factors. However, its high content of water-soluble carbohydrates contributes to the activity of Clostridia to form butyric acid and silage with low palatability. Therefore, ensiling should include the use of inoculants such as Lactobacillus casei LC.

In this study, we hypothesized that mulberry silage may have a positive effect on rumen fermentation, digestion, and nutrient absorption due to its high content of polyphenols and flavonoids.

Hu lambs (a breed that originates from Mongolian sheep and is well adapted to the hot climate prevailing in central China) were offered mulberry silage as a partial replacement for corn silage and soybean meal in the diet.

The effect of substitution on growth performance, gastrointestinal HEALTH, rumen fermentation parameters and microbial diversity in lambs was tested.

In the experimental diets, replacing 20–60% of corn silage with mulberries, the soy FLOUR content was adjusted while increasing the inclusion rate of mulberry silage in an attempt to balance the crude protein content of the diets.

Mulberry silage had a higher crude protein content and lower acidic and neutral detergent fiber content compared to corn silage.

The substitution did not affect the feed intake and growth rate of the lambs (feeding and average daily gain was similar to the control diet), but an increase in norank_f__F082 bacteria in the rumen was noted.

The normal rumen pH range is 6.0–7.5, and in this study, the pH gradually increased with the addition of mulberry silage, but everything remained within the normal range.

Findings. Compared to corn silage, the mulberry product showed some nutritional benefits, although this was not reflected in body weight gain. The reduced fiber content appears to delay the development of rumen papillae, which may explain why the improved nutrient content did not result in a clear weight gain.

Replacing corn silage and soybean meal with mulberry silage improved rumen fermentation patterns and possibly optimized nitrogen utilization.

Although mulberry silage may cause changes in rumen histological morphology and rumen microbial composition, bacterial diversity scores did not change significantly, indicating that the rumen fermentation status remained stable after mulberry silage was added to the diet. Thus, it is possible to replace corn silage by 20-40%.”