# Effects of Dietary Protein and Fat Levels on Growth Performance, Nutrient Digestibility, Serum Indexes, and Rectal Fecal Microbiota of Sika Deer (Cervus nippon) Fawns in Early Wintering Period

## TL;DR

This study found that a diet with 18% protein and 4% fat improves growth, digestion, and gut health in young sika deer during winter.

## Contribution

The study identifies an optimal protein-fat diet for sika deer fawns, linking it to enhanced growth and gut microbiota.

## Key findings

- Deer on 18% protein and 4% fat diets had higher weight gain and better nutrient digestion.
- This diet improved serum health markers and gut microbiota composition.
- Lower serum urea indicated better nitrogen utilization in the P18E4 group.

## Abstract

Feeding young sika deer the right balance of protein and fat is crucial for their growth and health. In this study, 32 young male sika deer were divided into four groups and fed different diets for two months to determine how protein and fat levels affect their development. The results showed that deer fed a diet with 18% protein and 4% fat grew faster, had better digestion of key nutrients, and showed improved health markers in their blood compared to the other groups. Additionally, this group exhibited enhanced gut microbiota. These findings suggest that a diet with 18% protein and 4% fat supports healthy growth, nutrient absorption, and gut health in young sika deer, helping them thrive during early winter. This research provides valuable insights for improving feeding strategies in deer farming, promoting better animal health and productivity.

This study examined the effects of dietary crude protein (CP: 18%, 15%) and crude fat (EE: 8%, 4%) levels, and their interactions, on growth performance, nutrient digestibility, serum indices, and rectal fecal microbiota in sika deer fawns during early wintering. A two-month 2 × 2 factorial experiment was conducted using 32 healthy five-month-old male fawns randomly assigned to four groups: P18E8 (18% CP, 8% EE), P18E4 (18% CP, 4% EE), P15E8 (15% CP, 8% EE), and P15E4 (15% CP, 4% EE). The P18E4 group showed the highest total weight gain and average daily gain (p < 0.05), along with greater apparent digestibility of dry matter, crude protein, calcium, and fiber fractions (p < 0.05). Serum urea content was significantly lower in this group, indicating improved nitrogen utilization (p < 0.05). Dominant fecal microbiota at the phylum level across all groups included Firmicutes_A and Bacteroidota, with the P18E4 group showing a unique genus composition within Bacteroidota, known for enhancing fiber digestion. In summary, a diet with 18% CP and 4% EE optimized growth performance, nutrient digestibility, and gut microbiota composition, providing a strategy for improving the health and productivity of sika deer fawns during overwintering.