Improvement of Kolbroek Boar Growth Performance and Carcass Quality through Dietary Crude Protein Supplementation

Abstract

Kolbroek pigs have numerous advantages as an indigenous breed including its contributions to food security. However, there are numerous concerns over the current feed regime that compromises its growth performance and carcass quality. Therefore, this study was conducted to evaluate the growth performance traits, attainment of puberty, backfat thickness (BFT), and carcass traits when boar fed diets supplemented with 10% (standard diet), 13% and 16% crude protein. Fifteen pigs per protein diets were individually housed and fed ad-libitum for eight weeks in a complete randomised design. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were measured on a weekly basis. At the end of the trial, all boars were slaughtered and carcass quality parameters measured. Pearson’s correlation coefficients were calculated between growth performance parameters. Our data revealed that there was an increase in final body weight, ADG, ADFI accompanied by decreases in BFT and the age of attainment of puberty. There was also a positive correlation between ADFI and ADG (r = 0.78) accompanied by a low positive correlation between ADG and BFT (r = 0.12) with a high negative correlation between FCR and ADG (r = -0.94). The water holding capacity (WHC), dressing percentage and marbling mass appeared to decrease while the eye muscle area increased with protein supplementation of the diet. There were also increases in the lungs, liver, small plus large intestines and stomach with no changes in the pancreas and heart tissues. Accompanying these was observations that the meat colour lightness improved accompanied by a decline in meat redness and yellowness. In conclusion, supplementation of boar diet with increasing crude protein improved the carcass quality and growth performance of Kolbroek boars.