Effects of sources and routes of administration of vitamins A, D and copper on postnatal status of these micronutrients in piglets.

Twenty-six nulliparous sows were fed conventional gestation and lactation diets supplemented (N = 13) or not (N = 13) with extra daily supplements of 25-hydroxy-cholecalciferol (25-OH-D3; 4 ĸIU), ß-carotene (24 ĸIU), and copper (Cu)-proteinate (45 mg) from day 90 of gestation to 21 d of lactation (L21). In each litter, 10 piglets were divided into 5 pairs received, at 2 (L2) and 8 d (L8) of age, one of the five combinations of micronutrient sources and routes of administration (N = 260 piglets total). These neonatal treatments (N = 26 pairs or 52 piglets each) consisted of oral vitamin D3, retinol acetate and CuSO4 (T1); oral 25-OH-D3, ß-carotene, and Cu proteinate (T2); exposure to ultraviolet light (UVB), oral retinol palmitate and Cu gluconate (T3); intramuscular vitamin D3 and retinyl propionate and oral Cu acetate (T4); oral saline (CTRL). Oral or intramuscular provisions corresponded to 12 mg of Cu and 70 and 12 ĸIU of vitamins A and D, respectively. Blood samples were collected from all piglets at L2, L8, and L21 for determination of serum Cu, retinol, and 25-OH-D3. Body weight was measured at birth, L2, L8, and L21. Piglets were weaned at L21, and liver and blood samples were collected 2 d later to evaluate oxidative enzymes in blood and liver and hepatic ATP concentrations and expression of genes associated with antioxidant status. Sow treatments had marginal or no impacts on Cu, retinol, 25-OH-D3, or antioxidant status in piglet blood serum and liver. However, when supplements were given to piglets, hepatic Cu was 38% greater in for all treated piglets compared to CTRL (P < 0.01), hepatic retinol was 3 times higher in T1 than in CTRL (P < 0.01) and intermediate for other treatments whereas serum 25-OH-D3 was markedly increased with T2 and T3 at L8 and L21, respectively, compared to CTRL (Piglet treatment × Age interaction, P < 0.01). Concerning antioxidant activities, glutathione peroxidase, and superoxide dismutase were increased (P < 0.03) in plasma of T2 piglets whereas the highest values (P < 0.03) for indicators of oxidative damage to proteins were observed in T4 piglets. The study revealed that oral Cu proteinate from T2, oral retinol acetate from T1, oral 25-hydroxy-cholecalciferol from T2, and UVB light exposure from T3 were the most efficient ways of increasing the postnatal status of these micronutrients in suckling piglets and this may have some impacts on their peri-weaning antioxidant status.

Studying the Association between Antibiotic Resistance Genes and Insertion Sequences in Metagenomes: Challenges and Pitfalls.

Antibiotic resistance is an issue in many areas of human activity. The mobilization of antibiotic resistance genes within the bacterial community makes it difficult to study and control the phenomenon. It is known that certain insertion sequences, which are mobile genetic elements, can participate in the mobilization of antibiotic resistance genes and in the expression of these genes. However, the magnitude of the contribution of insertion sequences to the mobility of antibiotic resistance genes remains understudied. In this study, the relationships between insertion sequences and antibiotic resistance genes present in the microbiome were investigated using two public datasets. The first made it possible to analyze the effects of different antibiotics in a controlled mouse model. The second dataset came from a study of the differences between conventional and organic-raised cattle. Although it was possible to find statistically significant correlations between the insertion sequences and antibiotic resistance genes in both datasets, several challenges remain to better understand the contribution of insertion sequences to the motility of antibiotic resistance genes. Obtaining more complete and less fragmented metagenomes with long-read sequencing technologies could make it possible to understand the mechanisms favoring horizontal transfers within the microbiome with greater precision.

Modelling piglet growth and mortality on commercial hog farms using variables describing individual animals, litters, sows and management factors.

Increases in sow prolificacy have reduced piglet vitality, growth capacity and weight at weaning and even pig weight at slaughter. The aim of this study was to develop a model that predicts likelihood of mortality and weight at weaning. A database containing 3214 records of birth weight, weight gain at 24h, rectal temperature at 24h, litter size, age at weaning, fostering status, manual assistance of birth and oxytocin use as well as the corresponding 227 records of sow parity and feed intake was analysed using logit functions for mortality and linear functions for weaning weight. The best model of mortality predicted increased likelihood as birth weight, rectal temperature and 0-24h weight gain decreased and sow parity and time between births increased (P<0.01, χ2=2910). The best model of weaning weight predicted increases with increasing birth weight, 0-24h body weight gain, age at weaning and sow parity and decreases with increasing litter size at 24h (P<0.01; AICC=4324; RMSE=0.82). This study confirmed that birth weight and weight gain during the first 24h are the principal factors influencing piglet growth and pre-weaning mortality.