Frédéric Mercerand

Effect of 2-hydroxy-4-methylselenobutanoic acid as a dietary selenium supplement to improve the selenium concentration of table eggs1

The aim of this study was to compare the effects of a new organic Se [2-hydroxy-4-methylselenobutanoic acid (HMSeBA)] with routinely used mineral and organic Se sources (sodium selenite and selenized yeast) on chosen performance criteria and Se deposition in egg and muscle of laying hens. A total of 240 laying hens (40 wk of age) were randomly assigned to 6 treatments for 56 d with 8 replicates of 5 hens per replicate. The 6 treatments were as follows: control group received basal diet without Se supplementation; the second, fourth, and sixth experimental groups (SS-0.2, SY-0.2, and HMSeBA-0.2, respectively) were fed basal diet supplemented with Se at 0.2 mg/kg from sodium selenite, selenized yeast, and HMSeBA, respectively; and the third and fifth experimental groups (SY-0.1, and HMSeBA-0.1, respectively) were fed basal diet supplemented with Se at 0.1 mg/kg from selenized yeast and HMSeBA, respectively. No difference was observed among dietary treatments on feed intake, egg weight, and laying rate. All hens fed the Se-supplemented diets exhibited greater total Se contents in their eggs compared with control hens (P < 0.01). The egg Se concentrations were greater in hens fed organic Se (HMSeBA-0.2, P < 0.01, and SY-0.2, P < 0.01) than those fed the SS-0.2. In addition, hens fed the diet with HMSeBA-0.2 accumulated more Se in their eggs (+28.78%; P < 0.01) and muscles (+28%; P < 0.01) than those fed the diet supplemented with SY-0.2. These results showed the greater ability of HMSeBA to increase Se deposition in eggs and breast muscle of laying hens, which can subsequently lead to greater supply of Se for humans.

2-Hydroxy-4-methylselenobutanoic acid induces additional tissue selenium enrichment in broiler chickens compared with other selenium sources

Two experiments were conducted in broiler chickens to compare the effect of different Se sources on Se tissue enrichment: sodium selenite (SS), seleno-yeast (SY), and a new organic Se source (SO) containing 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) as an active substance. For each experiment, treatments differed only in source or dose of Se additive. Relative efficiency was compared by plasma and tissue [muscle (pectoralis major) and liver] total Se concentrations. The first experiment compared Se sources (SS, SY, and SO) at different concentrations (mg of Se/kg of feed; SS-0.3; SY-0.1 and -0.3; SO-0.1 and -0.3; and a negative control, 0) in broilers between 0 and 42 d of age. Plasma, liver, and muscle Se concentrations were improved by all Se sources at both d 21 and 42 compared with the negative control group. Between Se sources, minor differences were observed for plasma and liver results, whereas a significant dose effect was observed from 0.1 to 0.3 mg of Se/kg of feed (P < 0.05) for each source. Muscle Se concentrations were improved such as SO > SY > SS (P < 0.05). Moreover, the relative muscle Se enrichment comparison, using linear regression slope ratio, indicated an average of 1.48-fold (95% CI 1.38, 1.58) higher Se deposition in muscle for SO compared with SY. In the second experiment, excessive dietary doses of 5 mg of Se/kg of feed from SS and SO showed a lower deleterious effect of SO on BW and feed intake in comparison with standard Se doses (P < 0.05). Seleno amino acid measurements conducted on different tissues of animals fed SO at 0.5 mg/kg of feed showed that HMSeBA is fully converted into selenomethionine and selenocysteine. These results of both experiments demonstrate the higher relative bioavailability of SO compared with SS and SY as determined through tissue Se enrichment.

Moderate Heat Challenge Increased Yolk Steroid Hormones and Shaped Offspring Growth and Behavior in Chickens

Background Environmental challenges might affect the maternal organism and indirectly affect the later ontogeny of the progeny. We investigated the cross-generation impact of a moderate heat challenge in chickens. We hypothesized that a warm temperature–within the thermotolerance range- would affect the hormonal environment provided to embryos by mothers, and in turn, affect the morphology and behavioral phenotype of offspring. Methodology/Principal Findings Laying hens were raised under a standard thermal condition at 21°C (controls) or 30°C (experimental) for 5 consecutive weeks. A significant increase was observed in the internal temperature of hens exposed to the warm treatment; however plasma corticosterone levels remained unaffected. The laying rate was not affected, but experimental hens laid lighter eggs than the controls during the treatment. As expected, the maternal thermal environment affected yolk hormone contents. Eggs laid by the experimental hens showed significantly higher concentrations of yolk progesterone, testosterone, and estradiol. All chicks were raised under standard thermal conditions. The quality of hatchlings, growth, feeding behavior and emotional reactivity of chicks were analyzed. Offspring of experimental hens (C30 chicks) were lighter but obtained better morphological quality scores at hatching than the controls (C21 chicks). C30 chicks expressed lesser distress calls when exposed to a novel food. Unlike C21 chicks, C30 chicks expressed no preference for energetic food. Conclusion/Significance Our findings suggest that moderate heat challenge triggers maternal effects and modulate the developmental trajectory of offspring in a way that may be adaptive. This suggests that the impact of heat challenges on captive or wild populations might have a cross-generation effect.

Short-term nutritional strategies before slaughter are effective in modulating the final pH and color of broiler breast meat

The poultry meat industry is faced with various quality issues related to variations in the ultimate pH of breast meat. The aim of this study was to evaluate the possibility to control breast ultimate pH by distributing finishing diets varying in amino acid (AA) and energy content for a short period before slaughter. Experimental diets were distributed to PM3 broilers on the last 3 d before slaughter (36 d of age). They consisted of a control (C) diet (3,150 kcal/kg; 200 g/kg of CP; 10.0 g/kg of true digestible Lys) with adequate amounts of AA other than Lys, 6 diets isocaloric to the control diet including 3 Lys-deficient (8.0 g/kg) diets with an adequate (Lys-/AA), low (Lys-/AA-), or high (Lys-/AA+) amount of other essential AA calculated in relation to Lys, and 3 Lys-rich (12.0 g/kg) diets with an adequate (Lys+/AA), low (Lys+/AA-), or high (Lys+/AA+) amount of other essential AA calculated in relation to Lys, and 2 diets isoproteic to C with a high (3,300 kcal/kg, E+) or low (3,000 kcal/kg, E-) energy content. Broiler feed consumption and growth performance were slightly affected by AA and energy content during the finishing period. Feed intake (33-36 d) was lower with the Lys+/AA+ and E+, and FCR between 24 and 36 d was higher with the Lys-/AA- and E- than with the C diet. Body weight at d 36 was lower in Lys-/AA-, Lys+/AA+, and E+ than in C, whereas the breast meat yield and abdominal fatness were not affected by diet. Lower pH values were observed in broilers fed Lys-deficient diets containing a high amount of other AA (Lys-/AA+) than in broilers fed diets containing low (AA-) or adequate (AA) amounts of other AA. This study shows that it is possible to alter the pH of breast meat by changing AA profile over a short period before slaughter, with limited impact on broiler growth and carcass composition.

Effect of different levels of feed restriction and fish oil fatty acid supplementation on fat deposition by using different techniques, plasma levels and mRNA expression of several adipokines in broiler breeder hens

Background Reproductive hens are subjected to a restricted diet to limit the decline in fertility associated with change in body mass. However, endocrine and tissue responses to diet restriction need to be documented. Objective We evaluated the effect of different levels of feed restriction, with or without fish oil supplementation, on metabolic parameters and adipokine levels in plasma and metabolic tissues of reproductive hens. Methods We designed an in vivo protocol involving 4 groups of hens; RNS: restricted (Rt) unsupplemented, ANS: ad libitum (Ad, receiving an amount of feed 1.7 times greater than animals on the restricted diet) unsupplemented, RS: Rt supplemented, and AS: Ad supplemented. The fish oil supplement was used at 1% of the total diet composition. Results Hens fed with the Rt diet had a significantly (P < 0.0001) lower growth than Ad hens, while the fish oil supplementation had no effect on these parameters. Furthermore, the bioelectrical impedance analysis (BIA) and the fat ultrasonographic examinations produced similar results to the other methods that required animals to be killed (carcass analysis and weight of adipose tissue). In addition, the Rt diet significantly (P < 0.05) decreased plasma levels of triglycerides, phospholipids, glucose and ADIPOQ, and fish oil supplementation decreased plasma levels of RARRES2. We also showed a positive correlation between insulin values and ADIPOQ or NAMPT or RARRES2 values, and a negative correlation of fat percentage to RARRES2 values. Moreover, the effects of the Rt diet and fish oil supplementation on the mRNA expression depended on the factors tested and the hen age. Conclusions Rt diet and fish oil supplementation are able to modulate metabolic parameters and the expression of adipokines and their receptors in metabolic tissue.

Bird's emotionality modulates the impact of chronic stress on feeding behaviour

Chronic stress is a long-lasting negative emotional state which induces negative consequences on animals’ behavior. This study aimed at assessing whether unpredictable and repeated negative stimuli (URNS) influence feeding behavior in quail, and whether this can be modulated by their emotionality. Two lines of quail divergently selected on their inherent emotionality (low emotionality, STI; high emotionality, LTI) were either daily exposed to URNS or undisturbed from 17 to 40 days of age (n=32 for each line, in each group). During this time, quail were submitted twice to a sequential feeding procedure: they were offered a hypocaloric diet (7% less caloric than the normocaloric diet) on odd days and a hypercaloric diet (7% more caloric) on even days, for 8 days; then, they received a normocaloric diet (metabolizable energy=12.56 MJ) for 3 days. This sequential feeding procedure was used to assess anhedonia and diet preferences thanks to choice tests (hypo vs. hypercaloric diets) performed at the end of each period. Short-term (30 min) and daily intake were also measured each day. Behavioral tests were performed to assess quail’s emotional reactivity. Results showed that URNS enhanced quails’ emotional reactivity, e.g. in the reactivity to human test, disturbed quail came later (P=0.011) and spent less time (P 0.1), but URNS reduced their daily intake during the 2nd period (P<0.05). Motivation for each diet (assessed by their short-term intake) was differently affected by URNS during the 2nd period: STI quail decreased their motivation to eat the hypercaloric diet (P<0.01) whereas LTI increased their motivation to eat the hypocaloric diet (P<0.01). In conclusion, both lines of quail experienced a chronic stress as URNS induced an increase of their emotional reactivity. Interestingly, URNS induced opposite changes in quail’s feeding behavior: LTI disturbed quail seemed to express a short-term compensatory behavior because of their high motivation to eat, whereas STI disturbed quail seemed to be in a devaluation process as shown by their anhedonia and their decrease of daily intake.Farm animals have to adapt to human presence from birth and being handled may lead to fear and stress reactions. It is known that the mother can be used as a postnatal model in the development of young-human relationship. Through her, some information like auditory ones may even be learnt prenatally. We tested this idea in pigs because they communicate a lot by acoustic signals. The hypotheses were that prenatal experience with human voice could modify behavioural reactions to the experienced voice and to an unfamiliar voice expressing different emotions. We worked with 30 pregnant sows from the last month of gestation. Ten sows (treatment A) were submitted to recordings of human voices during handling: vA during positive interactions and vB during negative interactions, twice a day, 5 days a week, for 10 minutes. Ten other sows (treatment B) received the contrary, i.e. vB during positive interactions and vA during negative interactions. Ten last sows (treatment C) received no vocal stimulations during handling sessions. Two days old piglets (36 A, 39 B, 35 C) were submitted to a 5 min choice test between voices vA and vB in a testing pen (2×1 m). Each voice was played back through loudspeakers positioned at each end of the pen. At 15-18 days of age, 20 other piglets from each treatment were tested in the same conditions except that we played back the voice of an unknown person, reading the same text with a joyful or angry intention. In both tests we recorded vocalisations and locomotion. Data were analysed using non parametric statistics (Statview). In both tests, A and B piglets started to move sooner (P 0.05) to be and the time spent (178 s (46s)) close to the loudspeakers did not depend on the treatment (P>0.05). We also found no difference between the time spent close to one loudspeaker or the other, neither for vA versus vB, nor for joyful versus angry intention (P>0.05). The results show that the prenatal experience of human voice reduces postnatal behavioural reactions of stress (vocalisations, latency to move) during the playback human voices. However, it does not seem to induce specific attraction toward human voice, or human emotional intention. Therefore prenatal experience with human voice may be a good way of reducing fear reactions to human voice after birth.