Effects of sex, litter size and periconceptional ewe nutrition on the ewe–lamb bond

Undernutrition restricted to the time around conception in sheep alters endocrine and metabolic responses in the offspring. Studies in rats suggest that such an early insult can also alter the behaviour of the offspring. We studied the effects of mild maternal periconceptional undernutrition (10–15% body weight reduction) on the lamb's response to separation from and reunion with the mother, and on the ewe–lamb bond, evaluated as the preference for each other over an alien ewe/lamb in a test enclosure, at 24 h, 1 and 4 weeks of age. Lamb birth weight was not affected by maternal nutrition. Maternal periconceptional undernutrition did not affect the lambs’ responses to separation and reunion (number of vocalisations, times to leave pen and achieve proximity with ewes) or the bond between ewes and lambs (percentage of time spent near their own dam/lamb). However, there were effects of sex, litter size and time on lambs’ responses to separation and reunion and on the ewe–lamb bond. Female lambs vocalised more during separation (P ≤ 0.01) and left the holding pen faster than males (P ≤ 0.05), and twins vocalised more than singletons (P ≤ 0.05). The time to leave the holding pen, achieve proximity with the ewes and number of vocalisations decreased with increasing postnatal age of the lamb (all P ≤ 0.001). Ewes showed a stronger preference for the lamb at 24 h and 1 week than at 4 weeks postpartum (P ≤ 0.001), whereas lambs followed an opposite trend, showing a lower preference for the mother at 24 h and 1 week and increased preference at 4 weeks of age (P ≤ 0.001). We conclude that periconceptional undernutrition does not affect offspring response to separation from the mother or the bond between ewes and lambs, but that these behaviours are affected by sex and litter size for up to 4 weeks after birth.     

Selective mortality and the anthropometric status of children in low- and middle-income countries

Despite a close relationship between the childrens’ anthropometric status and mortality rates, the highest mortality rates are concentrated in sub-Saharan Africa, while the lowest anthropometric indicators, in particular the height-for-age z-scores, are concentrated in South Asia. This discrepancy should, however, be expected to decrease when one accounts for the survivorship bias, i.e. selective mortality. We analyse whether the survivorship bias can explain these observed differences in three standard anthropometric indicators (stunting, underweight and wasting) by using individual data of children from six waves of Demographic and Health Surveys for a large cross-section of 37 low- and middle-income countries between 1991 and 2016. We use both a matching approach and semi-parametric regression to estimate the values for the anthropometric status of deceased children. The results are twofold: first, both methods reveal that the imputed values for the anthropometric indicators are, on average, between 0.10 and 0.25 standard deviations lower than the observed anthropometric indicators. Second, since the share of deceased children in our sample is below ten per cent, the contribution of the anthropometric status of deceased children to overall anthropometric indicators is small and therefore only influences it marginally.     

Early and Long-term Undernutrition in Female Rats Exacerbates the Metabolic Risk Associated with Nutritional Rehabilitation

Human studies have suggested that early undernutrition increases the risk of obesity, thereby explaining the increase in overweight among individuals from developing countries who have been undernourished as children. However, this conclusion is controversial, given that other studies do not concur. This study sought to determine whether rehabilitation after undernutrition increases the risk of obesity and metabolic disorders. We employed a published experimental food-restriction model. Wistar female rats subjected to severe food restriction since fetal stage and controls were transferred to a moderately high-fat diet (cafeteria) provided at 70 days of life to 6.5 months. Another group of undernourished rats were rehabilitated with chow. The energy intake of undernourished animals transferred to cafeteria formula exceeded that of the controls under this regime and was probably driven by hypothalamic disorders in insulin and leptin signal transduction. The cafeteria diet resulted in greater relative increases in both fat and lean body mass in the undernourished rats when compared with controls, enabling the former group to completely catch up in length and body mass index. White adipose tissues of undernourished rats transferred to the high-lipid regime developed a browning which, probably, contributed to avoid the obesigenic effect observed in controls. Nevertheless, the restricted group rehabilitated with cafeteria formula had greater accretion of visceral than subcutaneous fat, showed increased signs of macrophage infiltration and inflammation in visceral pad, dyslipidemia, and ectopic fat accumulation. The data indicate that early long-term undernutrition is associated with increased susceptibility to the harmful effects of nutritional rehabilitation, without causing obesity.     

Combined Prebiotic and Microbial Intervention Improves Oral Cholera Vaccination Responses in a Mouse Model of Childhood Undernutrition

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Commensal Bacteria Modulate Immunoglobulin A Binding in Response to Host Nutrition

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Characteristics of norepinephrine stimulated thermogenesis in undernourished subjects

Thermoregulatory thermogenesis was evaluated in chronically undernourished subjects as well as normally nourished controls by 60 min infusions of norepinephrine at a calculated dose of 0.15 μg/kg fat free mass/min. There was a significant (P< 0.05) reduction in the thermogenic response to norepinephrine in the undernourished labourers. When the characteristics of response were evaluated, the baseline and peak responses were comparable in both groups. However, the steepness of the response was greater (P< 0.05) in the undernourished subjects. The time to register a threshold response of 5 ml per min increase in oxygen consumption over the baseline after the start of infusion was longer in undernourished (about 20 min) as compared to the controls (about 10 min). It appears that, while the undernourished subjects have a reduced thermogenic component in their energy output, their peak capacity or potential for regulatory thermogenesis is the same as that in control subjects, since their thermogenic response has a greater slope. It is possible that chronically undernourished subjects may have a suppressed response over shorter periods of stimulation (less than 20 min), that is, before steady state thermogenic responses are achieved.