# Mulberry Silage as Alternative to Soybean Meal Protein in Ruminant Diet: Effect on Growth Performance, Digestion, Antioxidant Capacity, and Carcass Characteristics of Goats

## TL;DR

This study shows that mulberry silage can replace soybean meal in goat diets, improving growth, meat quality, and health, though full replacement has some drawbacks.

## Contribution

The study introduces mulberry silage as a viable alternative to soybean meal in ruminant diets, with detailed effects on digestion, growth, and meat quality.

## Key findings

- Mulberry silage increased feed intake of dry matter, protein, and fiber in goats.
- MS-100 improved growth performance but reduced digestibility of organic matter and fiber.
- MS-50 maximized meat amino acid content, while MS-100 enhanced antioxidant capacity and carcass weight.

## Abstract

Using 45 Xiangdong black goat kids split into three groups, the study examined substituting mulberry silage for soybean meal protein in goat diets at 50% and 100% substitution levels. The findings indicate that whereas full replacement (MS-100) decreased the digestibility of organic matter and fiber, mulberry silage enhanced feed intake of dry matter, protein, fiber, and organic matter. Health indicators improved; MS-100 goats had higher levels of antioxidant capacity, albumin, calcium, and plasma protein, but they also had higher levels of oxidative stress markers. While MS-50 maximized the amino acid content of meat, MS-100 improved growth performance with higher body weight, daily gain, and carcass weight. All things considered, mulberry silage shows promise as a substitute for soybean meal, promoting growth, health, and meat quality in goats that were either equivalent or better.

Current research is still striving to maximize the expansion of protein feed sources in order to reduce the production costs of the livestock industry. In this context, the current study aimed to evaluate the impacts of replacing soybean meal protein in diets with mulberry silage (at 50 and 100% substitution levels) on the growth, health status, and carcass characteristics of growing goat kids. Forty-five Xiangdong black goat kids weighing 18.2 ± 1.6 kg (approximately 6 months old) were divided into three experimental groups and fed one of the following diets: a control diet consisting of a 50:50 concentrate-to-roughage ratio on a dry matter basis (control), a diet replacing 50% of soybean meal protein with mulberry silage (MS-50), or a diet replacing 100% of soybean meal protein with mulberry silage (MS-100). The results show that replacing soybean meal protein with mulberry silage significantly increased (p < 0.05) the intakes of dry matter (DMI), crude protein (CPI), neutral detergent fiber (NDFI), and organic matter (OMI). However, no significant (p > 0.05) differences were observed in the digestibility of dry matter (DM), crude protein (CP), ether extract (EE), or neutral detergent fiber (NDF) among the groups, whereas the digestibility of OM and acid detergent fiber (ADF) was significantly reduced (p < 0.05) in the MS-100 group. Additionally, the MS-100 group exhibited significantly higher (p < 0.05) plasma total protein, albumin, and calcium levels. Total antioxidant capacity (TAC) was significantly enhanced in both the MS-50 and MS-100 groups compared to the control, although the MS-100 showed a significant increase (p < 0.05) in malondialdehyde (MDA) levels related to the other groups. In terms of growth performance, the MS-100 group improved (p < 0.05) final body weight, average daily gain, and carcass weights. Meanwhile, the MS-50 group recorded the highest contents (p < 0.05) of the following amino acids: aspartic acid, threonine, serine, glutamic acid, alanine, lysine, and proline. Overall, the results of the present study indicate that replacing soybean meal protein with mulberry silage generally produced comparable impacts, with additional positive effects on growth performance, meat quality, and health status of goats.