Developing a Reference Framework for Typical Development in the Young Pig

Abstract

Objectives The majority of infants in the US do not receive exclusive breastfeeding in the first six months of age, highlighting the necessity of infant formula. The artificially reared piglet is a common model utilized to support substantiation of novel bioactive components in milk or infant formula. However, it is currently unclear to what extent maternal and environmental rearing confounders affect growth outcomes in early life nutrition piglet studies. The objective of the present work is to use historical data to begin to chart typical development of the pig and to develop healthy reference value ranges for the purpose of assessing the safety of bioactive components in infant formula. Methods 8 piglet studies conducted at the University of Illinois Urbana-Champaign over the past ten years were compiled to create and model reference values for body and organ weights in artificially-reared and sow reared pigs. Metadata were organized to include milk replacer sources, bioactive components, sex, breed, source of herd, feeding rates, rearing styles, and health status. A combination of statistical models including simple linear regression, polynomial regression, and generalized additive models were used to analyze how such parameters influence typical growth. The diet of the 18 studies were blinded during data modeling phase. Results Over 13,000 data points from over 500 animals were identified to be suitable for data mining. Minimal differences in the growth of artificially or sow reared pigs were observed in the first 30 days of life (P > 0.05). Similarly, male and female bodyweight growth were nearly identical (P > 0.05). Development outcomes such as brain, liver, and intestinal organ weights were classified as typical for developing pigs. A subset of the data containing subjects with poor growth was identified to model growth under deficient or sub-optimal conditions. Conclusions The use of artificial rearing had no impact on body weight, nor did sex contribute to differences in growth during early life. Ultimately, these data can be used to create preliminary weight-for-age charts in the pig model to better interpret whether bioactive ingredients tested in the pig model affect animal growth within typical reference values. Funding Sources Funding was provided by Mead Johnson Nutrition, LLC, a Reckitt Benckiser LLC company.

Evaluation of 2’-Fucosyllactose and Bifidobacterium longum Subspecies infantis on Growth, Organ Weights, and Intestinal Development of Piglets

“…Experimental diets and probiotic treatments were successfully administered, and Bi-26 stored frozen in glycerol stock remained viable throughout the study ( Table S1 ). There was no significant treatment differences in any of the assessed behavioral or general demeanor outcomes and piglets in all groups demonstrated a typical pattern of body weight gain for artificially reared animals in the PNCL facility [ 26 ]. Although animals were allowed ad libitum access to the diets, relative formula intake over the course of the study did not differ between treatments, with an average of 316.9 ± 11.6 mL/kg BW/d ( p = 0.419).…”

“…The present study showed that supplementation with 2’-FL and Bi-26 individually or together lowered daily weight gain and together tended to lower total body weight gain compared to the CON formula. However, it should be noted that piglets demonstrated a typical growth pattern for piglets raised in the artificial rearing system in our facility [ 26 ] and total weight gain in the treatment groups was only ~5% lower than control; thus, it is likely that they difference body weight would not be of clinical relevance.…”

“…The experiment was conducted in five cohorts. Piglets of only one sex (male) were chosen to reduce any source of variation; although it was recently demonstrated that body and organ growth does not differ for pigs in the age range used in this study [ 26 ].…”