A systematic review of the efficacy of complementary colostrum, milk, and oral nutritional and dietary solutions on the health, growth, and gut health of suckling piglets.

Pre-weaning mortality has increased with the adoption of highly prolific sow genetics. To mitigate these limitations, alternative strategies have been investigated, including supplementation with heterologous or artificial colostrum or milk (derived from different species, eg, bovine, ovine) and the use of nutritional additives, such as proteins, pre/probiotics, vitamins, and bioactive compounds to replicate the protective functions of porcine colostrum and milk. This review aims to summarize and critically evaluate the effects of early dietary interventions, including cross-species colostrum, milk replacers, and oral functional additives, on suckling piglets, focusing on survival, growth performance, and gut health-related parameters, including intestinal function, immune and oxidative status parameters, and microbial establishment. The systematic literature search was conducted using Google Scholar, PubMed, Scopus, and Web of Science, employing the search "Colostrum" AND "piglets" OR "pig"; "Milk" AND "piglets" OR "pig" until 2023. A total of 7,251 articles were identified, and 62 were retained after filtering. The selected articles were categorized into three databases: 1) Colostrum, including trials with oral colostrum interventions and swine colostrum as a control group (14 articles); 2) Milk, focusing on milk-based oral interventions with a swine colostrum or milk as control group (12 articles); and 3) Oral strategies, comprising additive-based oral interventions (eg., prebiotics, probiotics, amino acids, and combinations) with controls receiving only colostrum, milk, or water (41 articles). Although many of these alternatives partially fulfill the nutritional requirements of neonatal piglets, results across studies remain inconsistent and controversial. Milk replacers closely approximate the composition of porcine colostrum and can improve piglet growth, including low-birth-weight piglets, while also exerting positive effects on intestinal structure, immune system, and intestinal microbiota. Additional benefits may be obtained through the supplementation of other bioactive compounds (amino acids, probiotics), although the optimal dosage and timing of administration remain to be determined. To date, no substitute has proven fully capable of replicating the complex and unique functional properties of porcine colostrum. This highlights the need for continued research to develop more effective interventions that can support piglet survival and performance.