Effects of feeding plant additives rich in saponins and essential oils on the performance, carcass traits and conjugated linoleic acid concentrations in muscle and adipose tissues of Black Bengal goats

Abstract

A study was undertaken to investigate the feeding of plant additives containing high concentrations of saponins (Acacia concinna pods; AC) and essential oils (Syzygium aromaticum buds; SA) on growth performance, feed utilization and concentrations of fatty acids (FA) including conjugated linoleic acids (CLA) in muscle and adipose tissues of Black Bengal goats. Eighteen growing goats (initial body weight of 7.97±0.34kg and the age of 6–8 months) were equally divided into three groups (control, AC and SA) in a randomized complete block design. All goats were fed the same concentrate mixture containing sunflower oil at 66.7g/kg dietary dry matter (DM) and berseem hay ad libitum in the ratio of 60:40. The AC and SA were added at the rate of 5.0 and 2.5g/kg DM, respectively to the concentrate mixture. A metabolic trial was conducted after 90 days of feeding, and carcass traits and FA composition of longissimus dorsi muscle and subcutaneous adipose tissues were determined at day 121 of feeding. Plant additives did not affect (P>0.05) average daily gains, feed intake, digestibilities of nutrients and N balance in goats. Feeding of plant additives also did not affect (P>0.05) carcass traits, and concentrations of protein, fat and ash in muscle. Addition of SA decreased (P<0.01) the proportion of total saturated FA, but increased the proportion of total polyunsaturated FA (PUFA; P<0.032) in both muscle and adipose tissues. Proportions of total CLA and cis-9, trans-11 CLA tended (P<0.10) to increase in muscle and adipose tissues owing to the inclusion of SA in the diet. However, feeding of SA decreased (P<0.01) the biohydrogenation of 18:2n-6 and complete hydrogenation to C18:0 and C22:0. Feeding of AC did not exert any effects (P>0.10) on the composition of FA in muscle and adipose tissues. Concentrations of serum glucose, cholesterol, protein and triglyceride were not altered by any additives. In conclusion, feeding of SA at 1.5g/kg of DM may improve the concentrations of beneficial FA in meat without any adverse effect on digestibility and growth performance in Black Bengal goats.