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The contexts in which individuals demonstrate behavioural consistency or variability have been the subject of research focus. We studied exploratory and sheltering behaviour in the crayfish F. virilis to understand how these behaviours vary by sex and reproductive readiness and to quantify the repeatability of these behaviours. Crayfish were tested in two sets of three rounds, one in the summer non-reproductive season and another in the autumn reproductive season. Reproductive crayfish spent more time outside the shelter and were more likely to accept a food item than non-reproductive crayfish. In the non-reproductive season, females spent more time outside the shelter than males, and over both seasons, females were more likely to seek and accept a food item. Repeatability estimates were low, indicating high intra-individual variability in these behaviours. Sheltering and exploratory behaviours were not correlated. This indicates sex or reproductive readiness have strong effects on both sheltering and exploratory behaviours.

Gestational health challenges may influence growth performance and immunity of offspring pigs during postnatal life. In particular, porcine reproductive and respiratory syndrome virus (PRRSV) is endemic in the U.S. herd, but its effects on surviving piglets are largely unknown. Further, dietary supplementation with soy isoflavones lessened the severity of PRRSV infections in weaning and growing pigs. Therefore, the goals of this study were to determine the impact of maternal PRRSV infection on offspring muscle and immune development and the potential of isoflavones to mitigate those effects. Thirteen first parity gilts were randomly allotted to 1 of 3 treatments: fed a diet devoid of isoflavones and not infected (CON), fed the control diet and infected with PRRSV (POS), and fed the control diet supplemented with 1,500-ppm soy isoflavones and infected with PRRSV (ISF). Isoflavone supplementation reduced (P = 0.04) viral load in dams 21d after infection, but did not alter (P > 0.05) feed disappearance and rectal temperature. Piglet mortality was increased (P = 0.04) by PRRSV infection in dams, and surviving piglets were infected with PRRSV throughout the study. Interestingly, muscle and organ weights were not different (P > 0.05) among treatments at postnatal d (PND) 3 with the exception of relative liver weight which was increased (P = 0.04) in POS compared with CON, with ISF being intermediate. Infected litters were lighter (P = 0.02) at PND 21, likely due to postnatal infection. Interestingly, at PND 21 relative liver weight was increased (P < 0.01) in ISF compared with CON and POS. Muscle fiber number and size did not differ between treatments (P ≥ 0.39). Piglets born to infected dams had slower responses during innate immune stimulation (P < 0.01) and also had shifts in T cell populations compared with CON pigs (P ≤ 0.02), indicating an inadequate vaccine response. Overall, maternal infection altered offspring immune responses but not muscle fiber development. Isoflavone supplementation did not mitigate these effects.

The objective of this study was to determine the effect of chronic inflammation during late gestation on offspring muscle development. Starting at gestational day (GD) 70, first-parity gilts were administered either lipopolysaccharide (LPS, n=7) or saline (CON, n=8) via jugular venipuncture every other day until GD 84. LPS was initially given at 10 µg/kg BW and was increased by 12% each instance of administration. Volume of PBS was increased accordingly. Rectal temperatures of gilts were collected at 0, 2, 3, and 4-h post injection. Gilts farrowed naturally at GD 114 (±2). At postnatal day (PND) 3, the pig closest to the average litter weight was euthanized, and the longissimus dorsi, psoas major, semitendinosus, heart, lungs, liver, and kidneys dissected and weighed. The semitendinosus was frozen in liquid N cooled-methylbutane and sectioned for muscle fiber typing analysis. Data were analyzed as a one-way ANOVA with cohort as a random effect and significance considered at (P ≤ 0.05). Gilts exposed to LPS had a 1.3°C increase in rectal temperature at 3 and 4-h post injection (P < 0.05), indicating successful induction of an inflammatory response. LPS exposure reduced (P = 0.04) the weight of piglets born alive and tended to reduce (P =0.09) the weight of piglets weaned, but did not alter the percent of pigs born alive or survival during the suckling period (P ≥ 0.29). Semitendinosus weight was also reduced (P < 0.01) in LPS pigs, and tended to be reduced (P =0.09) as a percentage of whole-body weight. However, there were no differences between treatments in any other tissues. Further, maternal LPS exposure did not alter fiber type proportions, average fiber area, or estimated number of fibers (P ≥ 0.17). Overall, these data indicate that chronic maternal LPS exposure during late gestation did not reduce offspring muscle fiber formation.

The objective of this study was to determine the effect of chronic inflammation during late gestation on offspring muscle development. Starting at gestational day (GD) 70, first-parity gilts were administered either lipopolysaccharide (LPS, n=7) or saline (CON, n=8) via jugular venipuncture every other day until GD 84. LPS was initially given at 10 µg/kg BW and was increased by 12% each instance of administration. Volume of PBS was increased accordingly. Rectal temperatures of gilts were collected at 0, 2, 3, and 4-h post injection. Gilts farrowed naturally at GD 114 (±2). At postnatal day (PND) 3, the pig closest to the average litter weight was euthanized, and the longissimus dorsi, psoas major, semitendinosus, heart, lungs, liver, and kidneys dissected and weighed. The semitendinosus was frozen in liquid N cooled-methylbutane and sectioned for muscle fiber typing analysis. Data were analyzed as a one-way ANOVA with cohort as a random effect and significance considered at (P ≤ 0.05). Gilts exposed to LPS had a 1.3°C increase in rectal temperature at 3 and 4-h post injection (P < 0.05), indicating successful induction of an inflammatory response. LPS exposure reduced (P = 0.04) the weight of piglets born alive and tended to reduce (P =0.09) the weight of piglets weaned, but did not alter the percent of pigs born alive or survival during the suckling period (P ≥ 0.29). Semitendinosus weight was also reduced (P < 0.01) in LPS pigs, and tended to be reduced (P =0.09) as a percentage of whole-body weight. However, there were no differences between treatments in any other tissues. Further, maternal LPS exposure did not alter fiber type proportions, average fiber area, or estimated number of fibers (P ≥ 0.17). Overall, these data indicate that chronic maternal LPS exposure during late gestation did not reduce offspring muscle fiber formation.