Effect of dietary supplementation of rubber seed kernel pellet on feed utilization, rumen fermentation, fatty acid profiles and health status in swamp buffalo

Abstract

Objective: Rubber seed kernel is a by-product of rubber cultivation and are high in oil and protein. This study was conducted to evaluate the effect of supplementing rubber seed kernel pellet (RUSKEP) on feed intake, nutrient digestibility, rumen fermentation, rumen fatty acid profiles, blood parameters, and immune response in swamp buffalo. Methods: Four male swamp buffalo with an initial body weight (BW) of 254±10 kg and 26 months of age were used in this research. The experimental design was a 4×4 Latin squared design with RUSKEP supplementation at 0%, 4%, 6%, and 8% of dry matter intake (DMI). Animals were fed concentrate at 1.0% BW, while rice straw was fed ad libitum. Results: Supplementation with RUSKEP did not change DMI or nutrient digestibility (p>0.05), while ether extract digestibility increased cubically with the addition of RUSKEP (p<0.01). The ruminal pH, ammonia-nitrogen (NH3-N), and the proportion of acetate (C2) were similar among treatments (p>0.05). The proportion of propionate (C3) increased linearly (p≤0.04), leading to a decrease in the acetate to propionate ratio (C2:C3) (p≤0.04) with the addition of RUSKEP. Furthermore, the butyrate (C4) proportion decreased linearly with RUSKEP supplementation (p = 0.03). The addition of RUSKEP did not affect on linoleic acid (C18:2 cis-9,12+trans-9,12), or α-linolenic acid (C18:3 cis-9,12,15) (p>0.05). With RUSKEP supplementation, the stearic acid (C18:0) content increased quadratically (p<0.01). The increasing level of RUSKEP was higher in cholesterol and eosinophils (p≤0.03). The immune function (IgA, IgM, and IgG) was similar among treatments (p>0.05). Conclusion: Supplementing RUSKEP with up to 8% of DMI could improve rumen fermentation efficiency without affecting feed utilization, rumen PUFA profile, or immune response in swamp buffalo.