Developing a Reference Database for Typical Body and Organ Growth of the Artificially Reared Pig as a Biomedical Research Model

Abstract

Objectives: The pig is a common model utilized to support substantiation of novel bioactive components in infant formula. However, reference ranges for outcomes to determine safety are unclear. Our objective was to use historical data to objectively define typical body and organ growth metrics of the domesticated pig in research.Methods: Twenty-two studies were compiled to assess typical growth of body and organ weights in young pigs. Metadata were organized to include milk replacer sources, bioactive components, sex, breed, source of herd, feeding regimen, and rearing environment. A combination of statistical models including simple linear regression and linear mixed effect models were used to assess typical growth patterns.Results: Over 18,000 data points from 786 animals were available. In general, minimal differences in the growth of pigs who were male and female, artificially- or sow-reared, or fed ad libitum- or by scheduled-feeding, were observed in the first 30 days of life (P > 0.05). A weight-for-age chart from reference pigs was developed to compare body weights of pigs demonstrating growth characterized as accelerated, typical, reduced, and failure to thrive to illustrate effects of dietary interventions. Distributions of relative brain, liver, and intestine weights (as % of total body weight) were similar between rearing environments and sexes. An alternative bivariate level approach was utilized for the analysis of organ weights. This approach revealed significant biologically-relevant insights into how deficient diets can affect organ weight that a univariate level assessment of weight distribution was unable to detect.Conclusions: Ultimately, these data can be used to better interpret whether bioactive ingredients tested in the pig model affect growth and development within typical reference values for pigs in the first 30 days of life.

Evaluation of the Safety of a Plant-Based Infant Formula Containing Almonds and Buckwheat in a Neonatal Piglet Model

“…Furthermore, the similar observations in body weight and kcal intake throughout the experiment between the dairy-based and plant-based formula fed animals showed that the plant-based formula utilized in the current study also supported adequate growth in those piglets. The daily body weight measured in all the piglets was in line with the growth reported in sow-fed piglets during the neonatal phase [ 22 , 23 , 24 ] or soy-fed piglets reported by others [ 25 ], and in line with our previous findings, in which piglets received pasteurized human milk, dairy-based milk formula or sow-fed piglets [ 26 ]. Additionally, the gastrointestinal tract development as well as that of the organs examined were similar between both dietary groups and are comparable with neonatal piglets that received a dairy-based milk formula [ 27 ] or soy formula [ 28 ] for 21 days.…”

Determining the safety and efficacy of dietary supplementation with 3ˊ-sialyllactose or 6ˊ-sialyllactose on growth, tolerance, and brain sialic acid concentrations

“…These results are congruent with previous studies, which also indicated a lack of difference in overall growth performance due to supplementation of 3ˊ-SL or 6ˊ-SL in pigs ( 16 , 17 , 23 , 35 ). In terms of body tissues, brain and liver weights for all treatments at PND 33 were also similar to those from previous studies ( 16 , 17 , 36 ). Despite 6ˊ-SL pigs having heavier absolute brain weights at PND 61, brain and liver weights relative to body weight did not differ by dietary treatment, which indicates similarities in allometric organ growth.…”