# Comparative Growth Performance and Intestinal Morphological Development Between Liangshan Yanying Chicken and Arbor Acres Chicken During the Brooding Stage

## TL;DR

This study compares the growth and gut development of two chicken breeds, finding that Arbor Acres chickens grow faster due to better intestinal structures.

## Contribution

The study identifies early intestinal morphological differences as a key factor limiting growth in local chicken breeds.

## Key findings

- Arbor Acres chickens had 3.24 times higher body weight at 28 days compared to Liangshan Yanying chickens.
- Arbor Acres chickens showed better feed efficiency and intestinal villus development.
- Liangshan Yanying chickens have longer intestines, likely adapted to high-altitude environments.

## Abstract

This research compares the growth and gut development of Liangshan Yanying Chicken and AA Broilers during their first 28 days. The study aims to understand why local breeds grow slower by examining their intestinal structures. Findings show that AA Broilers grew over three times larger and used feed much more efficiently. This advantage is linked to their superior gut structure, featuring higher density and longer villi—tiny projections that absorb nutrients. These features provide a larger surface area for digestion and lower energy costs for maintenance. While Liangshan Yanying Chicken grows more slowly, its longer intestines reflect an adaptation to its native high-altitude environment. The study concludes that early gut development is a primary factor limiting the growth of local breeds. This is valuable to society as it supports the genetic improvement of Liangshan Yanying Chicken, helping to preserve local poultry resources and meet the demand for high-quality meat.

The differences in growth performance and intestinal morphology between Liangshan Yanying Chicken (YYJ) and Arbor Acres (AA) broilers during the brooding stage, and to explore the effect of early intestinal development on growth. A total of 120 one-day-old male chicks of each breed were selected and randomly divided into three groups, reared under the same conditions for 28 days to measure body weight, feed intake, and intestinal morphological indices. The results showed that the body weight of AA broilers at 28 days of age was 3.24 times that of YYJ; the average daily gain and average daily feed intake from 1 to 28 days of age were 3.11 and 2.36 times those of YYJ, respectively, while the feed conversion ratio decreased by 24.10% (p < 0.01). Regarding intestinal morphology, the density of each intestinal segment in AA broilers remained significantly higher than that in YYJ. At 1 day of age, the villus height of the duodenum and ileum was 14.44% and 39.20% higher, respectively (p < 0.05 or p < 0.01), and the villus-to-crypt ratio in most intestinal segments at various ages was 78.27% to 91.05% higher (p < 0.01). Correlation analysis indicated that body weight at 14 and 28 days of age was significantly positively correlated with the average daily gain of each stage (p < 0.01), and significantly negatively correlated with the feed conversion ratio (p < 0.01). These findings indicate that the difference in early intestinal morphological development may constitute a key factor contributing to the growth limitation of local chicken breeds. This study provides a theoretical basis for the genetic improvement and nutritional regulation of YYJ.