Effects of different levels of coconut oil supplementation on performance, digestibility, rumen fermentation and carcass traits of Malpura lambs

The influence of coconut oil (CO) supplementation (0, 25, 50 and 75 g/kg of concentrate) upon performance, nutrient utilization, rumen fermentation, blood biochemistry and carcass characteristics were assessed in lambs (4 males and 4 females in each treatment) between 15d of age and 6 months. Lambs were allowed to suckle twice daily until 90d of age. Concentrate and forage (Ailanthus excelsa leaves) were provided ad libitum for the duration of the experiment. Lambs were weighed at weekly intervals, and a metabolism study was conducted on six representative lambs from each group at 120d of age to determine nutrient utilization and N balance. Blood samples and rumen liquor samples were drawn at 180d to determine blood biochemical and rumen fermentation characteristics. At 6 months of age all the male lambs were slaughtered and carcass traits were evaluated. Coconut oil intake was 7.1, 13.8 and 18.8 g/d in three treatment groups compared to zero in control. Pre- and post-weaning gain was similar while dry matter intake was higher in both pre-weaning (L: P < 0.001; Q: P < 0.001) and post-weaning (L: P=0.001; Q: P=0.001) in control. Digestibilities of organic matter (P=0.013) and neutral detergent fiber (P=0.062) decreased and that of ether extract increased (P=0.001) linearly with increased CO supplementation. The N retention decreased linearly (P=0.001) with increasing CO supplementation. Concentration of total N and trichloroacetic acid precipitable N decreased at a decreasing rate (Q: P=0.051 and P=0.019, respectively) whereas ammonia N in rumen liquor decreased at an increasing rate (Q: P=0.003) with increased CO supplementation. Coconut oil supplementation linearly (P=0.006) reduced rumen protozoa population. Though the concentration of serum glucose was similar, serum cholesterol and non-esterified fatty acids increased linearly (P < 0.05) with CO supplementation both pre- and post-weaning. Pre-slaughter weight, dressed weight, eye muscle area, and body fat were similar in all the lambs. Coconut oil supplementation up to 50 g/kg is optimum in lamb rations due to improved feed conversion ratio and production of a carcass with acceptable characteristics. Higher levels of CO supplementation depressed growth and feed conversion due to its suppression of rumen protozoa and reduced fiber digestibility. (C) 2010 Elsevier B.V. All rights reserved.