Effects of Supplementation of Synbiotic (DiPro Plus) on Growth Performance, Health Status, Skeletal parameters and Blood Parameters in Holstein Suckling Calves

Prior to weaning, dairy calves are vulnerable to various pathogens and nutritional challenges. For many years, antibiotics have been employed to address these issues while also providing economic advantages by enhancing calf performance and lowering medication expenses. However, the use of antibiotics in livestock management is under scrutiny due to concerns about microorganisms developing antibiotic resistance. To eliminate antibiotics from animal feed, numerous alternatives have been suggested, including probiotics, prebiotics, and Synbiotics. Prebiotics and probiotics, along with their combinations, can serve as alternatives to treat gastrointestinal tract (GIT) disorders and enhance the host's immune system. Prebiotics are non-digestible oligo-and polysaccharides that cannot be broken down by digestive enzymes, allowing gut microbes to utilize them for growth and development. Common prebiotics, such as oligosaccharides and dietary fibers, are employed for their health benefits. Oligosaccharides may also play a role in regulating rumen fermentation by raising protein and volatile fatty acid levels while lowering ammonia nitrogen. Probiotics, which are beneficial live microorganisms, help protect the GIT from pathogens and encourage the production of substances that combat these harmful microbes. Recently, probiotics have been recognized for their ability to improve animal health, growth performance, nutrient digestibility, gut microbial balance, and immune responses. Synbiotics, a combination of prebiotics and probiotics, may offer synergistic health benefits, improving the survival and colonization of beneficial microorganisms in the GIT more effectively than either prebiotics or probiotics alone. However, there is a lack of research on the impact of synbiotic supplementation on suckling calves. Therefore, the present study was carried out to investigate the effect of synbiotic DiPro Plus on growth performance, health status and some blood parameters of Holstein suckling calves. This study was conducted in Animal Husbandry dairy herd of Moghan Agro-Industrial (Parsabad, Ardabil province, Iran). Thirty-two newborn Holstein calves with an average age of 1 to 5 days and an average weight of 37±1 kg were randomly divided into four experimental groups in a completely randomized design (8 calves / group) for 63 days. The experimental treatments include: 1) Basal diet without additives, 2) Basic diet with 1.5 g of synbiotic per day, 3) Basic diet with 3 g of synbiotic per day, 4) Basic diet with 4.5 g of synbiotic per day. The diet containing feed and milk was given at two times a day i.e. in the morning (8:00 am) and evening (18:00 pm). Daily feed intake (DFI) was measured by measuring daily feed offered and refusal. Body weight change was determined on 42 and 63 of experimental period before the morning feeding. The morphometric measurements related to skeletal growth in calves were taken at birth, 42 days, and at the end of the study using a tape measure. Blood samples were taken from all calves from jugular veins puncture on the 30 and 63th of trial to measure blood metabolites concentrations. The fecal scores and overall health status of the calves were assessed daily according to the rating system developed by the University of Wisconsin (Health Score Chart, Wisconsin). In this system, a score of zero was assigned for optimal health and fecal condition, while a score of three indicated the worst health and fecal quality. Statistical analysis was performed based on ANOVA, general linear model procedure by SAS software. The results showed that the addition of 4.5 g of synbiotic in the milk of scukling calves increased the final weight and average daily gain compared to the control group (P < 0.05). The feed conversion ratio was not affected by different synbiotic levels. At the end of the experiment, the calves receiving synbiotic had greater height from the withers and body length compared to the control group (P < 0.05), but Heart girth and hip width were not affected by different levels of symbiotic (P > 0.05). Calves receiving 3 and 4.5 g of synbiotic in milk caused a significant increase in glucose and total protein concentration compared to 1.5 g of synbiotic and the control group on day 35 and 63 (P < 0.05). But the concentration of triglyceride could not be affected by different levels of synbiotic. The results showed that the use of 4.5 g of synbiotic improved the feces consistency compared to the control group, and the health condition of the calves receiving synbiotic was better than the control group (P < 0.05).Supplementing with synbiotics is an important strategy for enhancing growth and mitigating the adverse effects associated with raising calves. Synbiotics are recognized for their positive influence on feed intake, growth performance, and gastrointestinal health. Our results demonstrated a favorable impact on nutrient consumption, average daily gain, and a decrease in fecal scores. The findings of this study indicated that synbiotic formulations significantly influenced the daily weight gain of calves by positively affecting the beneficial microbiota in the gastrointestinal tract, leading to improved nutrient absorption and, consequently, better growth rates. In conclusion, the findings of this study indicate that 4.5 g of Synbiotic (DiPro Plus) as fermented milk was beneficial in terms of average daily gain, average daily gain, and reduced faecal score and diarrhea incidence. Additionally, suckling calves showed improvements in Withers height Abd body length. However, further research is required to fully understand the fundamental aspects of future synbiotics research on structure and gut microbiota, as well as host-microbe relationship. Similarly, there is a need to investigate the feasibility of developing a commercial synbiotic formulation for use as prophylaxis in pre-ruminant calves. In summary, the supplementation of 4.5 g of synbiotic in the diet of suckling calves provided benefits in terms of feed intake, average daily gain, reduced fecal scores, and decreased incidence of diarrhea. But the feed conversion ratio of suckling calves was not significantly affected by supplementation of synbiotic. Additionally, suckling calves exhibited improvements in withers height and body length. However, further research is needed to comprehensively understand the essential aspects of future synbiotic studies, particularly regarding the structure and gut microbiota, as well as the host-microbe relationship.