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

Abstract

BackgroundIn 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.ResultsA 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).ConclusionsThis 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.

Gut microbiota of newborn piglets with intrauterine growth restriction have lower diversity and different taxonomic abundances

“…A recent study found that the relative abundance of Firmicutes is associated with energy intake from the diet (Turnbaugh et al ); a higher proportion of the Firmicutes phylum was found in obese children and adults than lean individuals. In the present study, the lower relative abundance of Bacteroidetes and Firmicutes in IUGR piglets than controls suggests that IUGR piglets are less efficient at extracting energy from their diet and consequently gain less weight (Matheson et al ). In addition, Proteobacteria , which includes a wide variety of pathogens (such as Escherichia , Salmonella , Vibrio , Helicobacter and Yersinia ), is associated with inflammation (Cordonnier et al ; Wang et al ).…”

The challenge of large litters on the immune system of the sow and the piglets

“…Large litters are often including more reduced-birthweight piglets with characteristics of IUGR (Matheson et al, 2018;Yuan et al, 2015) showing physiological dysfunctions including hypoglycaemia, temperature instability, and increased neonatal morbidity and mortality (Aucott, Donohue, & Northington, 2004). IUGR piglets are characterized by a low birthweight and a dolphin-like head conformation (Hales, Moustsen, Nielsen, & Hansen, 2013).…”

“…Large litters have a direct impact also on piglets at birth. The higher is the number of piglet born in a litter, the lower is the piglet birthweight ( Figure 2) and the higher is the variation in piglet birthweight within the litter (Akdag, Arslan, & Demir, 2009;Beaulieu, Aalhus, Williams, & Patience, 2010;Matheson, Walling, & Edwards, 2018;Quesnel, Brossard, Valancogne, & Quiniou, 2008;Smit et al, 2013). A greater number of piglets born than the available teats at the sow's udder, a lower birthweight and a greater birthweight variation all increase the piglets' competition for colostrum intake (Declerck, Sarrazin, Dewulf, & Maes, 2017).…”

“…In large litters, an increased number of piglets born with signs of intrauterine growth retardation (IUGR) is also reported. These piglets have an extremely lower birthweight and lower vitality (Amdi et al, 2013;Matheson et al, 2018). A reduced colostrum intake in the first 24 hr of life has negative effects on the piglet survival (Devillers, Le Dividich, & Prunier, 2011).…”

Developments of reproductive management and biotechnology in the pig

“…Furthermore, hyperprolific sows give birth to more piglets with low birth weight and with signs of intrauterine growth restriction (IUGR). There is an inverse relationship between number of piglets born in a litter and piglet birth weight; large litters are also associated with high variation in piglet birth weight within the litter (Quesnel et al, 2008;Akdag et al, 2009;Beaulieu et al, 2010;Smit et al, 2013;Matheson et al, 2018). A greater number of piglets born than the available teats at the sow's udder, lower birth weight and greater birth weight variation increase piglet competition for colostrum intake (Declerck et al, 2017).…”