Maternal nutrition and fetal imprinting of the male progeny

The global population as well as the demand for human food is rapidly growing worldwide, which necessitates improvement of efficiency in livestock operations. In this context, environmental factors during fetal and/or neonatal life have been observed to influence normal physical and physiological function of an individual during adulthood, and this phenomenon is called fetal or developmental programming. While numerous studies have reported the impact of maternal factors on development of the female progeny, limited information is available on the potential effects of fetal programming on reproductive function of the male offspring. Therefore, the objective for this review article was to focus on available literature regarding the impact of maternal factors, particularly maternal nutrition, on reproductive system of the male offspring. To this end, we highlighted developmental programming of the male offspring in domestic species (i.e., pig, cow and sheep) as well as laboratory species (i.e., mice and rat) during pregnancy and lactation. In this sense, we pointed out the effects of maternal nutrition on various functions of the male offspring including hypothalamic-pituitary axis, hormonal levels, testicular tissue and semen parameters.

Evaluation of Feeding Beta-Hydroxy-Beta-Methylbutyrate (HMB) to Mouse Dams during Gestation on Birth Weight and Growth Variation of Offspring

This study was designed to determine if feeding β-hydroxy-β-methylbutyrate (HMB) to pregnant mice would improve birth weight uniformity and growth performance of offspring. Dams (Agouti Avy) were assigned to one of four treatments: control (CON; n = 13), low-level HMB (LL; 3.5 mg/g; n = 14), high-level HMB (HL; 35 mg/g; n = 15), and low-level pulse dose fed from gestational days 6 to 10 (PUL; 3.5 mg/g; n = 14). Randomly selected dams (n = 27) were euthanized on gestational day 18 to collect placentae and pup weights. The remaining dams gave birth and lactated for 28 days. Dams only received HMB during gestation. Dietary HMB did not influence the performance of dams. Dietary treatment during gestation did not affect litter size or birth weight of pups. Variation was not different among treatments in terms of birth weight of offspring. Placental weights were not affected by treatments. Overall, growth performance of offspring after weaning was similar among all treatments. Body composition of offspring at 5 and 8 weeks of age was similar regardless of HMB treatment during gestation. In conclusion, dietary HMB supplementation in pregnant mice did not affect birth weight, variations in birth weight, or growth performance of offspring.

Management and Feeding Strategies in Early Life to Increase Piglet Performance and Welfare around Weaning: A Review

The performance of piglets in nurseries may vary depending on body weight, age at weaning, management, and pathogenic load in the pig facilities. The early events in a pig's life are very important and may have long lasting consequences, since growth lag involves a significant cost to the system due to reduced market weights and increased barn occupancy. The present review evidences that there are several strategies that can be used to improve the performance and welfare of pigs at weaning. A complex set of early management and dietary strategies have been explored in sows and suckling piglets for achieving optimum and efficient growth of piglets after weaning. The management strategies studied to improve development and animal welfare include: (1) improving sow housing during gestation, (2) reducing pain during farrowing, (3) facilitating an early and sufficient colostrum intake, (4) promoting an early social interaction between litters, and (5) providing complementary feed during lactation. Dietary strategies for sows and suckling piglets aim to: (1) enhance fetal growth (arginine, folate, betaine, vitamin B12, carnitine, chromium, and zinc), (2) increase colostrum and milk production (DL-methionine, DL-2-hydroxy-4-methylthiobutanoic acid, arginine, L-carnitine, tryptophan, valine, vitamin E, and phytogenic actives), (3) modulate sows' oxidative and inflammation status (polyunsaturated fatty acids, vitamin E, selenium, phytogenic actives, and spray dried plasma), (4) allow early microbial colonization (probiotics), or (5) supply conditionally essential nutrients (nucleotides, glutamate, glutamine, threonine, and tryptophan).

Effects of L-Arginine Supplementation during Late Gestation on Reproductive Performance, Piglet Uniformity, Blood Profiles, and Milk Composition in High Prolific Sows

This study was conducted to evaluate the effects of L-arginine supplementation levels during late gestation on reproductive performance and piglet uniformity in high prolific sows. A total of 60 F1 multiparous sows (Yorkshire × Landrace), with an average body weight of 238.2 kg, were allotted to one of three treatment groups in a completely randomized design. The dietary treatments were divided by the supplementation level of arginine during the late-gestation period, from day 70 to farrowing, as follows-(1) CON: corn-soybean meal-based basal diet (Arg 0.72%), (2) Arg10: basal diet + L-Arg 0.28% (Arg 1.0%), and (3) Arg15: basal diet + L-Arg 0.79% (Arg 1.5%). The same lactation diet was provided ad libitum to sows during the lactation period. There were no significant differences in body weight and backfat thickness in sows during late-gestation and lactation. Dietary arginine levels had no significant influences on the number of total born, stillbirth, and born alive. However, increasing inclusion level of L-arginine supplementation tended to increase (p < 0.10) alive litter weight linearly, and also linearly increased (p < 0.05) the piglet weight gain and litter weight gain during the lactation period. In piglet uniformity, the standard deviation of piglet birth weight (p < 0.05) and the coefficient of variation for piglet birth weight (p < 0.10) increased linearly, as dietary arginine levels increased in the late gestation period. Increasing L-arginine supplementation to late gestating sows linearly increased (p < 0.05) the blood concentrations of arginine and ornithine at day 90 and day 110 of gestation. On the other hand, dietary arginine levels in late gestation did not affect the blood parameters related to the nitrogen utilization. Increasing dietary arginine levels for the late gestating sows did not affect the milk composition for colostrum and milk at day 21 of lactation. In conclusion, the inclusion level of arginine in the diet for late gestating sows, by up to 1.5%, could improve the alive litter weight at birth and litter weight gain during lactation, whereas the piglet uniformity at birth was decreased due to the increase of survival for fetuses with light birth weight.

Genetic selection against intrauterine growth retardation in piglets: a problem at the piglet level with a solution at the sow level

Background

In polytocous livestock species, litter size and offspring weight act antagonistically; in modern pig breeds, selection for increased litter size has resulted in lower mean birth weights, an increased number of small piglets and an increased number of those affected by varying degrees of intrauterine growth retardation (IUGR). IUGR poses life-long challenges, both mental, with morphological brain changes and altered cognition, and physical, such as immaturity of organs, reduced colostrum intake and weight gain. In pigs, head morphology of newborn piglets is a good phenotypic marker for identifying such compromised piglets. Growth retardation could be considered as a property of the dam, in part due to either uterine capacity or insufficiency. A novel approach to this issue is to consider the proportion of IUGR-affected piglets in a litter as an indirect measure of uterine capacity. However, uterine capacity or sufficiency cannot be equated solely to litter size and thus is a trait difficult to measure on farm.

Results

A total of 21,159 Landrace × Large White or Landrace × White Duroc piglets (born over 52 weeks) with recorded head morphology and birth weights were followed from birth until death or weaning. At the piglet level, the estimated heritability for IUGR (as defined by head morphology) was low at 0.01 ± 0.01. Piglet direct genetic effects of birth weight (h² = 0.07 ± 0.02) were strongly negatively correlated with head morphology (− 0.93), in that IUGR-affected piglets tended to have lower birth weights. At the sow level, analysis of the proportion of IUGR-affected piglets in a litter gave a heritability of 0.20 ± 0.06, with high and negative genetic correlations of the proportion of IUGR-affected piglets with average offspring birth weight (− 0.90) and with the proportion of piglets surviving until 24 h (− 0.80).

Conclusions

This suggests that the proportion of IUGR-affected piglets in a litter is a suitable indirect measure of uterine capacity for inclusion in breeding programmes that aim at reducing IUGR in piglets and improving piglet survival.

Ovarian follicle development and genital tract characteristics in different birthweight gilts at 150 days of age

In the last decades, selection for improved prolificacy has resulted in higher litter sizes and has thereby increased the proportion of low birthweight (LW) piglets. It is well documented that LW piglets have lower growth performance, muscle accretion and poor carcass quality. However, little is known about the relations of birthweight with subsequent reproductive performance in gilts. This study investigated the effects of birthweight on reproductive tract and ovarian follicle development in 150-day-old gilts. Twenty eight female pigs of different birthweight ranges (high-HW: 1.8-2.2 kg; low-LW: 0.8-1.2 kg) from higher parity commercial sows were reared until 150 days of age, and their body weights were recorded at weaning, end of nursery and end of the grower-finisher phase. The animals were killed and their reproductive tracts collected for biometrical and histomorphometrical analysis. LW gilts showed significantly lower body weights and growth rates during all phases of production compared to their HW counterparts (p < .01). Most biometrical measurements of the reproductive tract were similar between the experimental groups, except vaginal length and the gonadossomatic index (relative ovarian weight), which were affected by birthweight class (p < .05). LW females also showed fewer medium size (3-5 mm; p < .01) ovarian follicles, pre-antral follicles (p < .07) and more atretic follicles per ovarian cortex area (p < .05). Therefore, besides the effects on post-natal growth performance, birthweight affects vaginal length and the follicular dynamics process, which may impair the reproductive performance of replacement gilts.