The effect of fat type and l-carnitine administration on growth, feed digestibility and blood metabolites of growing Afshari lambs

Abstract

This study was conducted to evaluate the effect of fat type and l-carnitine supplementation on feed intake, nutrient digestibility, growth, and blood metabolites in growing Afshari lambs. Twenty-four-male lambs with an initial body weight of 16±0.4kg were used in a completely randomized design with a 2×2 factorial arrangement of fat type with or without supplemental carnitine in an 84-day feeding period. The diets were isoenergetic and isonitrogenous. Soybean oil or a commercial Ca-protected fat were included at 4% of the DM of diet, each with or without 100mg l-carnitine top dressed per kg of diet. Initial weight was equalized across treatments. At the end of experiment, blood was sampled from each lamb and concentrations of serum glucose, BUN, total protein, triglyceride, total cholesterol, HDL, and LDL were determined. There was no interaction between fat type and carnitine administration on feed intake, nutrient digestibility and growth. Fat type did not affect feed intake, but lambs fed soybean oil had greater DM and EE digestibility (P<0.05), and tended to have higher CP digestibility. Supplemental l-carnitine did not affect feed intake, but improved EE digestibility (P<0.01) and tended to improve CP digestibility (P=0.10). Although fat type did not affect growth of lambs, l-carnitine administration tended (P=0.13) to improve body weight and ADG, thus improving FCR (P<0.05). Fat type interacted with l-carnitine administration for cholesterol and LDL concentration in blood; l-carnitine administration significantly decreased them only for the soybean oil diet (P<0.05). Lambs fed with soybean oil, compared with Ca-protected fat, had more (P<0.05) total protein and BUN and tended (P=0.11) to have lower triglyceride concentrations in the blood. Under conditions of the current study l-carnitine might improve growth, dietary fat digestibility, and blood metabolites of lambs fed diets with supplemented fat. Supplementing different fat types had a minimal effect on responses of lambs.