Impacts of Graded Levels of Metabolizable Energy on Growth Performance and Carcass Characteristics of Slow-Growing Yellow-Feathered Male Chickens.

K F M Abouelezz,W Wang,X Lin,Q Fan,L Li,S Jiang,Z Gou,Y Wang

doi:10.3390/ani9070461

Abstract

Simple SummaryInadequate feed inhibits the potential performance of birds, and giving birds excess nutrients or levels higher than the requirement reduces production profits and may lead to negative effects on performance. Although recently there has been an expanding market worldwide for slower growing chickens to meet the consumer demand for a better tasting meat, little effort has gone into optimizing their dietary nutrient levels. Using fiv e different dietary energy levels, this study evaluated the optimal requirement of dietary energy for maximal growth rate, feed:gain ratio, meat quality indices, and blood metabolites of a Chinese yellow-feathered breed.A dose-response study was conducted to investigate the metabolizable energy (ME) requirement for Lingnan chickens from 9 to 15 weeks of age. One thousand two hundred 8-week-old slow-growing yellow-feathered male chickens were allotted to five dietary ME levels (2805, 2897, 2997, 3095 and 3236 kcal/kg). The results revealed that the daily metabolizable energy intake increased (p < 0.01), whereas the feed intake and feed:gain ratio decreased linearly (p < 0.01) with the increment in dietary ME level. The final body weight and daily gain of the highest ME treatment tended (p > 0.05) to be greater than those obtained with the lower ME levels. The fat content in breast muscle showed a quadratic response (p < 0.05) to the increase in dietary energy level. The shear force values of breast muscle in the 2897, 3095 and 3236 kcal/kg treatments were lower (p < 0.05) than those of the 2997 kcal/kg treatment. In conclusion, among the tested ME levels, 3095 kcal/kg was adequate for feed intake, shear force, and plasma uric acid, and 3236 kcal/kg tended to increase the body weight, body gain, and feed conversion ratio of Lingnan males between 9 and 15 weeks of age; further studies are still required for testing higher levels.

Highlights

In poultry production enterprises, feed cost accounts for around 70% of the total costs involved in production
As the dietary energy requirement for slow-growing yellow broilers has not been estimated or optimized, the present study has evaluated the effects of different dietary metabolizable energy (ME) levels on growth performance, blood biochemical variables, carcass quality, body composition, rate of energy deposition, and fat content in breast and thigh muscles
ME intake increased, but average daily feed intake (ADFI) and feed conversion ratio (FCR) decreased as linear responses to the increment in dietary energy level

Summary

Introduction

In poultry production enterprises, feed cost accounts for around 70% of the total costs involved in production. Among the different feed-stuffs used in formulating poultry diets, the source of dietary energy resources is a major cost; 70% of the total poultry diet content are energy sources. Animals 2019, 9, 461 dietary energy level, is important for lowering the feed cost per unit of poultry products [1]. Increasing dietary energy level provides fundamental benefits in the feed conversion ratio (FCR) of broilers, mostly by decreasing feed consumption [2,3,4]. The dietary energy can be optimized for both growth performance and for enhanced meat quality. Dietary nutrient levels alter meat color, energy content, and histological makeup as well as the metabolic characteristics of broiler muscles [5,6,7]

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Conclusion