👤 Parisa Rahimpour

Evidence has shown significant sex differences in freezing and darting behaviors in a rat model of aversive learning using fear conditioning. The present study explored sex differences in a rat model of aversive learning using a fear-conditioning method via measuring freezing and darting behaviors. Fear conditioning was induced by three footshocks (0.8 mA, 3 s, 30-s interval) paired with an auditory conditioned stimulus (75 dB, 3 s). Extinction was performed by broadcasting 20 auditory conditioned stimuli (75 dB, 3 s, 30-s interval), with no shocks, in three, or four, of five sessions. Freezing and darting behaviors, locomotor activity and time spent in the center squares (anxiety-like behavior) in the open field test, and brain-derived neurotrophic factor (BDNF) in the infralimbic region of the mPFC (medial prefrontal cortex) were evaluated. The results showed both sexes showed a high rate of freezing, with males showing more freezing. Females were more responsive to extinction. Darting behavior was only observed in females and diminished following extinction. Locomotion and anxiety-like behavior were increased and decreased following extinction learning in both sexes, respectively. BDNF expression level in the infralimbic region of the mPFC was increased following extinction learning, with a greater increase in females. In conclusion, we showed that females have a diverse behavioral response to the anticipation of a threat in a rat model of fear conditioning. The important role of BDNF in the modulation of both freezing and darting behaviors was also shown. Show less

Optimizing the use of dietary emulsifiers and prebiotics in relation to fat source may enhance nutrient-utilization efficiency in broiler production. This 42-d study evaluated the effects of an emulsifier (lysophospholipid; LPL) and inulin supplementation in diets with two fat sources on growth performance, nutrient digestibility, muscle fatty acid composition, digestive enzyme activity, and intestinal histomorphology. Eight hundred 1-d-old male broiler chickens were assigned to eight treatments in a 2 × 2 × 2 factorial design with two fat sources (soybean oil or beef tallow), two LPL levels (0 or 1 g/kg), and two inulin levels (0 or 1 g/kg). Interactive effects were detected for fat source × inulin on average daily gain (ADG), mortality, and the European Production Index (EPI), with inulin addition to soybean-oil-based diets yielding superior growth and survival rates (P < 0.05). The LPL × inulin interaction increased feed intake and improved gain-to-feed ratio (P < 0.05). The fat source × LPL interaction significantly influenced lipid-metabolism-related traits (P < 0.05); in tallow-based diets, LPL supplementation increased fat digestibility and AMEn, reduced breast fat deposition, and improved the fatty acid profile of thigh muscle by elevating n-3 PUFA and lowering the n-6/n-3 ratio, whereas no significant effects occurred in soybean-oil-based diets. When interaction terms were not significant, LPL increased protease and lipase activities and improved duodenal villus height and surface area, whereas inulin increased protease activity, improved protein digestibility, and enhanced jejunal villus architecture (P < 0.05). In conclusion, LPL is particularly beneficial in tallow-based diets by enhancing lipid digestibility, energy utilization, and the thigh-muscle fatty acid profile, while inulin improves growth performance, especially in soybean-oil-based diets-offering a practical strategy to optimize broiler production. Show less