Mango (Mangifera indica) seed kernels as untraditional source of energy in Rahmani sheep rations

Abstract

Abstract Background The present work aimed to investigate the impact of partial replacement yellow corn by mango seed kernels (MSK) at different levels of (0, 25, and 50%) on feed and water consumption, water metabolism, nutrient digestibility, nitrogen balance, and rumen fluid parameters. Methods Twelve mature male Rahmani sheep of about 58.39 ± 1.22 kg live body weight on average were used to investigate the influence of replacing yellow corn contents (45% in the control ration) by mango seed kernels (MSK) at different levels (0, 25, and 50%) that equal (0, 11.25, and 22.5% of total ration contents) on feed and water intakes, water metabolism, nutrient digestibility coefficients, nitrogen utilization, and some rumen fluid parameters. The animals were randomly assigned to three experimental groups (four animals in each treatment). Sheep fed rations are composed of 50% concentrate feed mixture (CFM) and 50% peanut vein hay (PVH) at portion 3% dry matter (DM) of live body weight (LBW). Results The results showed that values of crude protein (CP), crude fiber (CF), and nitrogen-free extract (NFE) of MSK and yellow corn were similar. Meanwhile, MSK has superior ether extract content compared to yellow corn; meanwhile, ash content of yellow corn was lower than ash content of MSK. All tested CFM were isonitrogenous (16.17% CP), but it differs in their contents of gross and digestible energy. On the other hand, all experimental total mixed rations (TMR) were isonitrogenous (14.52% CP) and isocaloric (4177 kcal/kg DM in average). Dietary treatments significantly (P < 0.05) decreased total dry matter intake (DMI) and crude protein intake (CPI) that expressed as (g/h/day, g/kgW0.75, and kg/100 kg LBW) or gross energy intake (GEI) and digestible energy intake (DEI) that expressed as (Mcal/h/day, kcal/kgW0.75, and Mcal/100 kg LBW). Inclusion MSK in sheep ration insignificantly (P > 0.05) increased drinking water by 20% and 6.89% for experimental groups fed TMR2 and TMR3, respectively, compared to the control one (TMR1). Incorporation MSK in the rations significantly (P < 0.05) increased insensible losses of water. Dietary treatments significantly (P < 0.05) increased nutrient digestibility coefficients of DM, organic matter (OM), CP, CF, and NFE. Meanwhile, it significantly (P < 0.05) decreased EE digestibility. On the other hand, both values of total digestible nutrient (TDN) and digestible crude protein (DCP) were significantly (P < 0.005) improved. Nitrogen retention (NR) (NR % of nitrogen intake (NI) and NR % of digested nitrogen (DN)) values were significantly (P < 0.05) increased with increasing level of MSK in the sheep ration. Inclusion MSK significantly (P < 0.05) increased ruminal pH; however, it had no significant (P > 0.05) on both ammonia nitrogen (NH3-N) and total volatile fatty acid (TFVA) concentrations. Sampling time at 3 h post feeding significantly (P < 0.05) decreased ruminal pH in comparison with before and 6 h post feeding; meanwhile, sampling time had no significant effect (P > 0.05) on NH3-N concentration. Dietary treatment significantly (P < 0.05) increased the interaction between treatments and sampling time for ruminal pH. However, no interaction between treatments and sampling time was observed for both NH3-N and TVFA concentrations. Conclusion The present results revealed that replacement up to 50% of yellow corn by MSK as alternative source of energy could be useful in feeding sheep without any adverse effect on digestion and fermentation processing. Also, it can be used to depress the rations cost.