The Suckling Rat as a Model for Immunonutrition Studies in Early Life

Figure 3

Diagram of the possible designs for experimental nutritional interventions beginning at gestation, through suckling and infancy to rat adult age and main physiological outcomes. (a) Nutritional interventions: maternal diet can be manipulated during gestation (3 wk) and/or suckling (3 wk) in order to transfer the nutrient to the offspring. During suckling, a precise amount of nutrient can be administered to pups by oral gavage. When the pups start eating the solid diet (2-3 wk), their diet can also be manipulated up to adult age. The objective of the study will lead the researcher to decide the interventional period (with the experimental diet) and the period in which the effect will be evaluated (end point of the design). (b) Physiological outcomes: samples from the gestating and lactating dams during the study period are needed to confirm nutrient incorporation and later transfer to pups (i.e., breast milk and plasma). Plasma and feces are noninvasive samples that can also be obtained periodically from the developing animals and are useful for immune determinations such as cytokines or immunoglobulins. At the end of the study, immune lymphoid tissues can be obtained for cell isolation and further phenotypic and/or functional studies (usually after ex vivo culture under stimulation).