Effect of amino acid enriched diets on hemolymph amino acid composition in honey bees.

Amino acids (AAs) are an abundant class of nectar solutes, and they are involved in the nectar attractiveness to flower visitors. Among the various AAs, proline is the most abundant proteogenic AA, and γ-amino butyric acid (GABA) and ß-alanine are the two most abundant non-proteogenic AAs. These three AAs are known to affect insect physiology, being involved in flight metabolism and neurotransmission. The aim of this study was to investigate the effects of artificial diets enriched with either ß-alanine, GABA, or proline on consumption, survival, and hemolymph composition in honey bees belonging to two different ages and with different metabolism (i.e., newly emerged and foragers). Differences in feed intake among diets were not observed, while a diet enriched with ß-alanine improved the survival rate of newly emerged honey bees compared to the control group. Variations in the hemolymph AA concentrations occurred only in newly emerged honey bees, according to the diet and the time of hemolymph sampling. A greater susceptibility of young honey bees to enriched diets than older honey bees was observed. The variations in the concentrations of hemolymph AAs reflect either the accumulation of dietary AAs or the existence of metabolic pathways that may lead to the conversion of dietary AAs into different ones. This investigation could be an initial contribution to studying the complex dynamics that regulate hemolymph AA composition and its effect on honey bee physiology.

NEFA, BHBa, UREA and Liver Enzyme Variation in the Bloodstream of Weaned Foals up to 18 Months of Age.

The pattern of selected metabolites for interpreting homeostasis during the growth of foals can be used as an indicator of energy balance state and liver health. Against this background, the literature on circulating parameters of foals across growth stages is scanty. We hypothesized that circulating metabolites indicating energy distribution such as non-esterified fatty acids (NEFA), ß-hydroxy-butyric acid (BHBa), UREA and liver enzyme-like γ-glutamyl-transferase (γ-GT) [interpreted in the light of circulating total bilirubin (TBIL), alanine aminotransferase (ALT) and aspartate aminotransferase (AST)] may be used to monitor the energy balance of growing foals. A total of 12 Anglo-Arab (AA) foals from the same stable were enrolled in this trial. All foals were serially weighed on a digital scale and sampled for total blood at weaning, at 12 and 18 months of age. Feeding and keeping conditions were similar for all the foals involved. Animals appeared healthy and no signs of poor growth performance were pointed out. The peak of circulating NEFA mobilized from body depots was reached at one year of age but markedly dropped at 18 months, when BHBa increased (p < 0.001) alongside with liver enzyme. BHBa and γ-GT levels turned out to positively correlate (p = 0.051). However, at 6, 12 and 18 months, γ-GT dropped in the physiological reference range for the horse, thus showing no prognostic value. ALT and UREA significantly increased (p = 0.008 and p = 0.006, respectively) when NEFA also increased (p = 0.001). Liver enzyme increase could be associated with fat mobilization and ketone bodies production meanwhile amino acid transamination for energy purposes led to the increase of UREA in the bloodstream. However, no prognostic value to liver enzyme could be attributed in this trial.

Effects of Dietary Zn/Se and α-Tocopherol Supplementation on Metabolic Milieu, Haemogram and Semen Traits of Breeding Stallions.

Trace element status and metabolic milieu are sometimes overlooked in common veterinary clinical practice across animal species. The evaluation of requirements of trace elements, in fact, may be useful to prevent the perturbation of tissue-specific metabolic impair. In particular, essential trace elements in the diet play key roles within sub-cellular metabolic patterns with macro effects at the systemic level, like blood cell stability and semen quality. This effect was studied in breeding stallions, in which semen quality and haemogram are important for reproduction. A case-control feeding trial involved 40 stallions (age: 8-21 years; body weight, BW: 510-531 kg) of one stud centre, allotted to two experimental groups (n = 20 control, CON vs. n = 20 supplemented, SUPPL100), following a matched-pairs approach based on age. Supplemented stallions (SUPPL100) received a mixed mineral and vitamin supplement of Zn/Se and α-tocopherol (α-TOH) (100 g/day stallion) to compound feed, fed as control diet to horses of the control group (CON). Horses resulted deficient in circulating α-TOH and Zn at the start, though clinically healthy. After supplementation, different plasmatic levels of α-TOH, Zn and Se were found between groups. Circulating basophils (BASO) and mean cell haemoglobin concentration (MCHC) were affected by the dietary treatment (p < 0.05). Plasmatic Se affected monocyte count, haematocrit, mean cell volume and mean cell haemoglobin concentration. Semen traits were not affected by the dietary treatment per se, except for mobile/progressive sperm cells (%) of stallions aged > 13 years marginal circulating levels of α-TOH (p = 0.04). Ameliorating the micromineral status showed to improve the haemogram of stallions in view of circulating levels of Cu. Semen quality appeared to be strongly dependent on animal effects.

Influence of partial replacement of soya bean meal by faba beans or peas in heavy pigs diet on meat quality, residual anti-nutritional factors and phytoestrogen content.

The study evaluated the partial substitution of soybean meal by faba beans (18%) or peas (20%) as additional protein sources in diets destined for typical Italian heavy pig production. It compared animal performances, meat quality, the presence of residual anti-nutritional factors (ANF) and phytoestrogens in plasma and meat and the possible effects on pig health, by evaluating oxidative, inflammatory and pro-atherogenic markers. The results showed that the productive performances, expressed as body weight and feed conversion ratio, of pigs fed with faba bean and pea diets were similar to those of pigs fed only the soybean meal. Meat quality of pigs fed with the three diets was similar in colour, water-holding capacity, tenderness and chemical composition. Despite the higher levels of phytoestrogen in the plasma of pigs fed only the soybean meal, phytoestrogen concentration in the muscle was equivalent to that of animals fed diets with faba beans, whereas pigs fed a diet with peas showed a lower concentration. Inflammation and pro-atherogenic parameters did not show significant differences among the three diets. Overall, the partial substitution of soybean meal by faba beans appears more interesting than with peas, particularly in relation to the higher amount of polyphenols in the diet and the highest concentration of phytoestrogens found in the plasma and muscle of animals, while the pyrimidine anti-nutritional compounds present in the diet did not appear to accumulate and had no effect on the growth performance of animals.

Brief note about plasma catecholamines kinetics and submaximal exercise in untrained standardbreds.

Four untrained standardbred horses performed a standardized exercise test on the treadmill and an automated blood collection system programmed to obtain blood samples every 15 s was used for blood collection in order to evaluate the kinetics of adrenaline and noradrenaline. The highest average values obtained for adrenaline and noradrenaline were 15.0 +/- 3.0 and 15.8 +/- 2.8 nmol/l respectively, with exponential accumulation of adrenaline (r = 0.977) and noradrenaline (r = 0.976) during the test. Analysis of the correlation between noradrenaline and adrenaline for each phase of the test shows that correlation coefficient decreases as the intensity of exercise increases (from r = 0.909 to r = 0.788). This suggests that during submaximal exercise, the process for release, distribution and clearance of adrenaline into blood circulation differs from that of noradrenaline.