Effect of Excess Levels of Dietary Crude Protein on Carcass Development in Swine

Abstract

Eighteen castrate, crossbred male pigs weighing 18 kg. initially were used to study the effects of widely different dietary crude protein levels (16 to 12%, 32% and 48%) on carcass development. Daily weight gain and feed consumption decreased as dietary protein level increased, but gain/feed ratios were similar among diets. As dietary protein level increased dressing percent and back fat thickness decreased, and percent four lean cuts increased. The net quantity of four lean cuts, however, did not differ among diets. The decrease in back fat thickness as dietary protein level increased from 16 to 12 to 32% was five times greater than that which occurred between 32 and 48% protein. The response of loin-eye area to dietary protein level was variable. The contents of moisture, crude protein and crude fat of liver, kidney and loin-eye muscle were determined. Moisture content of liver increased as dietary protein level increased.