Extracts of Apricot (Prunus armeniaca) and Peach (Prunus pérsica) Kernels as Feed Additives: Nutrient Digestibility, Growth Performance, and Immunological Status of Growing Rabbits

Abstract

This study assessed the effects of the kernel extracts of apricot (AKE; Prunus armeniaca) and peach (PKE; Prunus pérsica), and their mixture (Mix) on growth efficiency, feed utilization, cecum activity, and health status, of growing rabbits. Weaned male New Zealand White rabbits at six weeks old [n = 84, 736 ± 24 SE g body weight (BW)] were randomly allotted to four dietary groups. The first group received no feed additives (control), the second and third groups received 0.3 mL/kg BW of AKE and PKE, respectively, and the fourth group received a mixture of AKE and PKE (1:1) at 0.3 mL/kg BW (Mix). Results indicated that 2(3h)-Furanone, 5-Heptyldihydro was found in abundance in both extracts, while 1,1-Dimethyl-2 Phenylethy L Butyrate and 1,3-Dioxolane, and 4-Methyl-2-Phenyl- were the most components detected in AKE and Cyclohexanol and 10-Methylundecan-4-olide were found in abundance in PKE. All the experimental extracts enhanced (p < 0.05) the growth performance, cecal fermentation parameters, and cecal L. acidiophilus and L. cellobiosus count, while PKE and the mixture treatments presented the highest (p = 0.001) total weight gain and average weight gain without affecting the feed intake. Rabbits that received the mix treatment had the highest (p < 0.05) nutrient digestibility and nitrogen retained, and the lowest (p = 0.001) cecal ammonia concentration. All the experimental extracts enhanced (p < 0.05) the blood antioxidant indicators (including total antioxidant capacity, catalase, and superoxide dismutase concentrations), and immune response of growing rabbits. In general, fruit kernel extracts are rich sources of bioactive substances that can be used as promising feed additives to promote the growth and health status of weaned rabbits.