Effect of pelleted total mixed rations with different levels of intact rapeseed on performance, carcass traits, serum biochemical indices and meat quality of Boer goats

Abstract

The objective of this study was to investigate the effect of intact rapeseed (IR) supplementation in goat total mixed ration (TMR) pellets on performance, carcass traits, serum biochemical indices and meat quality. Forty-eight healthy Boer goats with similar initial bodyweight (12.52 ± 1.48 kg) were randomly assigned to four treatment groups, dietary containing 0%, 2.5%, 5.0% and 7.5% IR, respectively. The results showed that IR had no significant effect on weight gain and average daily feed intake, but 7.5% IR significantly decreased F/G (P<0.05). There were no significant difference among all groups in carcass weight, dressing percentage, visceral fat, liver, kidney and rumen weight, but IR significantly increased the rumen index (P<0.05). IR supplementation significantly increased serum total cholesterol, high density lipoprotein, low density lipoprotein and triglyceride level (P<0.05), but had no effect on serum free triiodothyronine, free thyroxine, aspartate aminotransferase or alanine aminotransferase level. In meat quality, IR had no significant influence on meat colour value, pH, water loss rate, cooked meat rate, crude protein, crude ash, total cholesterol content and amino acid composition, but could increase the meat fat content and the relative content of linolenic acid (C18:3, cis-9, 12, 15), eicosenoic acid (C20:1, cis-11) and decrease the relative content of palmitic acid (C16:0), margaric acid (C17:0) and heptadecenoic acid (C17:1, cis-10) (P<0.05). In conclusion, when adding amount in TMR pellets reached 7.5%, IR had almost no adverse effects on growth performance, carcass traits, liver and thyroid function of Boer goats. Conversely, it could reduce F/G and improve ruminal development and the meat quality to some extent.