Effects of dietary protein/energy ratio on growth performance, carcass trait, meat quality, and plasma metabolites in pigs of different genotypes.

Yingying Liu,Bi’E Tan,Yulong Yin,Jinping Deng,Guoli Jiang,Xiangfeng Kong,Xiaojian Yang,Xia Xiong,Fengna Li

doi:10.1186/s40104-015-0036-x

Abstract

BackgroundThe protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes.MethodsBama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups (Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment) in a 2 × 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases.ResultsWe observed significant interactions (P < 0.05) between breed and diet for total fat percentage, intramuscular fat (IMF) content, protein content in biceps femoris (BF) muscle, and plasma urea nitrogen (UN) concentration in the nursery phase; for average daily gain (ADG), average daily feed intake (ADFI), dry matter, IMF content in psoas major (PM) muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced (P < 0.05) growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher (P < 0.05) ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower (P < 0.05) feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN.ConclusionsCompared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.Electronic supplementary materialThe online version of this article (doi:10.1186/s40104-015-0036-x) contains supplementary material, which is available to authorized users.

Highlights

The protein/energy ratio is important for the production performance and utilization of available feed resources by animals
The present study focused on evaluating the effects of breed and dietary protein/energy ratio on growth performance, carcass composition, and meat quality
We found that Landrace pigs fed the NRC diet had lower plasma concentration of urea nitrogen (UN), whereas Bama mini-pigs fed the same diet had higher plasma concentration of UN, than did those fed the GB diet

Summary

Introduction

The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes. The pig is one of the most economically important species among domesticated livestock and is a major protein source for human consumption. A major objective of pig production is to increase skeletal muscle growth and reduce excess fat accretion. Livestock producers use nutritional modifiers in an attempt to increase protein accretion in the muscle, while they often simultaneously reduce fat deposition [1, 2]. The livestock industry faces the challenge of increasing the IMF content of pork so that consumers may have a satisfactory experience, while simultaneously producing minimal visible fat, which is a deterrent to health-conscious consumers

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