Dietary supplemental chromium and niacin influence the growth performance and fat deposition in lambs

Abstract

Context Nowadays fat is an unpopular constituent of meat for consumers and therefore, a decrease in fat-tail size is often desirable for producers. Feed additives like chromium (Cr) and niacin (B3) have been reported to improve meat quality in beef and dairy cattle. However, their effect on meat quality and performance of fat-tail breeds of finishing lambs is unknown. Aim The aim of this study was to investigate the effect of supplemental chromium (Cr) and niacin (B3) on performance and fat deposition of carcass of finishing lambs. Methods Twenty male Zandi lambs (23.7 ± 0.73 kg) were allocated into one of four treatments: (1) control; (2) 300 µg/ kg DM Cr as chromium methionine; (3) 200 mg/kg DM B3 as rumen-protected niacin; and (4) 300 µg/ kg DM Cr as chromium methionine + 200 mg/kg DM B3 as rumen-protected niacin. Key results Chromium and B3 supplementation decreased blood glucose, insulin, triglycerides and low-density lipoprotein levels (P < 0.05). Lambs fed diet supplemented with B3 consumed more feed with a higher growth (P < 0.05) compared with other groups. There were no significant differences in feed efficiency, hot carcass weight, and dressing percentage among experimental groups. However, there was a decrease in the subcutaneous, abdominal, tail and total carcass fat in Cr supplemented lambs (P < 0.01) compared with other experimental groups. The expression level of acetyl CoA carboxylase 1 (ACC1) and diglyceride acyltransferase 2 (DGAT2) genes was lower in Cr groups of lambs compared with other groups (P < 0.05). Conclusions These results indicated that organic Cr supplementation improved meat quality by reducing fat accumulation, whereas B3 supplementation resulted in higher growth rate and feed intake. Implications Results showed that chromium supplementation reduces expression level of acetyl CoA carboxylase 1 and diglyceride acyltransferase 2 genes resulting in lower level of subcutaneous, abdominal, tail and total carcass fat of finishing lambs.