Electrohydrodynamically microencapsulated, lyophilized, and fermented probiotics outperform in-feed antibiotics in promoting growth performance and gut health of Bos indicus calves

Abstract

Probiotics are increasingly explored as an alternative to antibiotics for improving calf health, however, their efficacy can be affected by the method of delivery and survival of viable cells within the gastrointestinal tract. Comparative studies evaluating different probiotic delivery systems against conventional antibiotic supplementation remains limited in calves. Therefore, this study aimed to investigate the effects of fermented, lyophilized, and encapsulated formulations of Lactiplantibacillus plantarum CRD7 and Lacticaseibacillus rhamnosus CRD11 with chlortetracycline on growth performance, immunity, and gut health in indigenous cattle calves. Forty calves (5–10 days old) were randomly assigned to five treatments (n = 8 per treatment) as follows: 1) control (CT), 2) supplementation with antibiotic (AT), 3) fermented milk probiotics (FP), 4) lyophilized probiotics (LP), and 5) encapsulated probiotics (EP). Probiotic supplementation improved (P < 0.001) net weight gain, dry matter intake, structural growth measurements (body length, wither height, heart girth, and hip height), and neutral detergent fibre digestibility compared with the CT and AT treatments. Calves receiving probiotics also exhibited lower (P < 0.001) fecal scores, pH, and ammonia concentrations, together with higher fecal concentrations of lactate and short-chain fatty acids. More importantly, EP and LP treatments increased (P < 0.001) fecal counts of Lactobacillus and Bifidobacterium and reduced abundance (P < 0.001) of E. coli and C. perfringens . In addition, superoxide dismutase activity (P < 0.001) and cell‐mediated (P < 0.05) and humoral immune responses (P < 0.001) were improved in EP treatment in comparison to other treatments. The present findings indicate that probiotic supplementation could enhance growth performance, improve immune status, and reduce diarrheal episodes by promoting beneficial gut microbiota of calves. From a practical perspective, this study demonstrates the potential of probiotic processing approaches, particularly encapsulation and lyophilization, as strategies to enhance probiotic efficacy and reduce reliance on antibiotics in dairy calf management, thereby contributing to sustainable livestock production.