Search

Background: Growing evidence suggests that the dietary ratio of linoleic acid (LA) to a-linolenic acid (ALA), the precursors of arachidonic acid (AA) and docosahexaenoic acid (DHA), respectively, may affect behavior in mammals. Objective: This study aimed at evaluating the impact of dietary LA and ALA intake on behaviors of growing pigs, a pertinent model for human nutrition. Methods: At 7 wk of age, 32 pigswere allocated to 4 dietary treatments varying in daily intake of LA (1.3 and 2.6 g ⋅ kg body weight-0.75 ⋅ d-1 for low- and high-LA groups, respectively) and ALA (0.15 and 1.5 g ⋅ kg body weight-0.75 ⋅ d-1 for low- and high-ALA groups, respectively) for 4 wk. Between days 12 and 18, general behavior in the home pen was observed and pigs were subjected to an open field and novel object test. At 11 wk of age, brain fatty acid composition was analyzed. Results: Compared with high LA intake, low LA intake increased the time spent on exploration, particularly nosing in the home pen (P < 0.05) and the open field (P < 0.05), and tended to reduce the time spent lying with eyes open in the home pen (P = 0.09). Time spent lyingwith eyes open also tended to be affected by the interaction between LA and ALA (P = 0.08). A high-LA/high-ALA intake (ratio of 2; P < 0.05) and a low-LA/high-ALA intake (ratio of 1; P = 0.06) decreased the latency to approach the novel object compared with a low-LA/low-ALA intake (ratio of 9). DHA in the frontal cortex was positively correlated with exploratory behaviors in the home pen (rs = 0.56, P < 0.01), whereas AA was negatively correlated with time spent lying with eyes closed (rs = -0.48, P < 0.01). Conclusions: Low LA intake and a low dietary LA:ALA ratio increased exploration and decreased anxiety-related behaviors in pigs. It is suggested that changes in brain DHA and AA induced by dietary LA and ALA intake mediate these behavioral changes. [ABSTRACT FROM AUTHOR]

Abstract: When exposed to novel food during food transitions, growing pigs often elicit a neophobic response that is responsible for decreased food consumption. Flavour preference conditioning may represent an interesting way to reduce neophobia and improve food intake in growing pigs. The present series of experiments investigated the pig''s conditioned preference for a flavoured beverage added with different carbohydrates and sweeteners and the possible transition of those beverage-induced preferences to flavoured solid food. In Experiment 1A, nine juvenile pigs were given three two-day conditioning sessions: they received a flavoured beverage added with 1.125% sucrose (F+S1.125) and a second flavoured beverage with no additive (F−). In Experiment 1B, nine juvenile pigs were given six two-day conditioning sessions: they received a flavoured beverage added with 10% sucrose (F+S10) and a second flavoured beverage with no additive (F−). In subsequent two-choice drinking tests, the pigs exhibited no clear-cut preference for F+S1.125, whereas F+S10 was preferred compared to F− (P <0.05) but only during the first subsequent two-choice drinking tests, suggesting that pigs developed a short-term preference for the flavour previously paired with 10% but not 1.125% sucrose. The Experiment 2 was conducted to assess the independent effects of visceral (caloric intake) and gustative (sweet taste) reinforcement in flavour preference conditioning. Nine juvenile pigs were subjected to four three-day conditioning sessions: they received flavoured beverages added with 2.25% maltodextrin (F+m, caloric intake), 0.37% saccharin (F+s, sweet taste), or no additive (F−). During further two-choice drinking tests, no clear-cut preference emerged, but the consumption of F+m was 107% and 35% higher than that of F− and F+s, respectively. Despite pigs exhibited some conditioned flavour preferences during two-choice drinking tests in Experiments 1B and 2, no clear-cut preference was observed during two-choice feeding tests with flavoured solid food. Overall, these findings highlight the importance of the combination and/or synergy between gustative and visceral reinforcements for conditioned flavour preference and suggest that a visceral reinforcement via maltodextrin might be sufficient to condition such a preference. Moreover, the absence of clear-cut preference during two-choice feeding test illustrates the difficulty to transpose a flavour preference acquired via a sweet beverage to solid food. Further studies are needed to investigate the failure of saccharin-conditioned preference in pigs. [Copyright &y& Elsevier]

• Stray currents < 0.5V in the environment generate moderate behavioural and physiological stress responses in pigs and might affect their health and welfare. • Pigs exposed to stray currents in the post-weaning unit spent less time in resting time and exhibiting socio-positive behaviours and, in the same time, pigs spent more time inactive in alert and exhibiting socio-negative behaviours. • The blood oxidative status was increased in pigs exposed to stray currents. With the modernisation of pig breeding facilities, pigs may be exposed to both on-farm and off-farm sources of stray voltages. Data from ruminant species suggest that exposition to stray voltages may be a source of stress and impair animal welfare, but data are scarce for pigs. The aim of this study was to evaluate the impact of stray currents of voltages under 0.5 Volts in pig housing on piglet behaviours and some biomarkers after weaning. Two replicates of 820 piglets were reared in a farm naturally exposed to stray voltage for seven weeks. The difference in electrical potential between the floor and each drinker and feeder was measured every two weeks. Piglets exposed to high-voltage drinkers (HVD > 125 mV) spent more time orally manipulating pen mates (P = 0.0031). They also spent more time lying inactive with open eyes (P = 0.0027) and less time nosing pen mates (P = 0.043), but these effects were influenced by the voltage in feeders (P = 0.0021 and P = 0.024, respectively). Piglets exposed to high-voltage feeders (HVF > 50 mV) spent less time lying with their eyes closed (P = 0.024) and more time aggressing pen mates (P = 0.0081). Fifty days after entering the farm, blood hydroperoxide concentration was higher in piglets exposed to HVD (P = 0.039). The increase in socio-negative behaviours and oxidative stress in pigs exposed to stray voltages in pig housing suggested that stray voltages might have moderate detrimental consequences for piglets in post-weaning facilities. [ABSTRACT FROM AUTHOR]