Essential methods for swine nutrition studies: A review

This review provides an overview of some of the major methodologies needed and commonly employed in swine nutrition studies, both before an experiment even commences and in the conduct of experiments. Proper methodology is critical for accurately assessing the effects of dietary interventions on a range of outcomes such as pig performance, nutrient utilisation and efficiency, and, increasingly, the environmental footprint impacts and evaluation of pork production. Swine nutrition experiments typically involve controlled feeding trials using well-defined animal groups based on age, body weight, and/or production stage (weaners, growers, finishers, and sows). Experimental designs such as randomised complete block or factorial arrangements are frequently used to examine different treatments, minimise variability, and ensure statistical reliability. Ingredient evaluation and feed formulation are central to these studies, relying on precise calculations of the contents of energy and/or nutrients according to established nutritional standards and measurements. Ingredients for studies are generally selected based on nutrient composition, digestibility and availability, although other influences such as palatability and anti-nutritional factors can be contemplated, and test diets are formulated to isolate the effect of for instance, specific nutrients or feed additives, on a range of outcomes. Ingredient and feed samples should be analysed according to the type of study being conducted, e.g., for proximate composition, amino acid profiles, energy content, using standardised laboratory techniques including near-infrared spectroscopy (NIRS), bomb calorimetry, or Kjeldahl nitrogen analysis. Animal performance is typically evaluated through measurements of feed intake, weight gain, and feed conversion efficiency, while digestibility trials typically include faecal and/or ileal sampling to determine nutrient and/or energy absorption efficiency and whole-body utilisation. Blood, tissue, microbiome and/or ‘omics’ analyses may be conducted concurrently to assess, for example, the metabolic, immune, and/or intestinal health responses to different nutritional interventions. Housing conditions, environmental control, and animal welfare standards are maintained according to institutional and ethical regulations for adherence to jurisdictional regulations and ensure reproducibility and validity of results. Overall, swine nutrition research and the myriad methodologies that underpin is a cornerstone for global pork production, integrating rigorous experimental design, accurate feed formulation, and comprehensive analytical methods to evaluate dietary effects on a host of different outcomes including growth performance, nutrient efficiency, and animal health, therefore providing critical data to improve feeding strategies and promote sustainable pork production globally.