The aim of this study was to investigate the effect of a dietary probiotic supplement on bone mass and meat quality of broiler chickens. Two hundred ten 1-day-old male Ross 708 broiler chicks were divided among 21 floor pens (10 chicks per pen). The pens were randomly distributed to 1 of 3 dietary treatments containing a probiotic, Bacillus subtilis, at 0 (control), 0.25 (0.25X), and 0.5 (0.5X) g/kg (n = 7). Gait score, footpad dermatitis (FPD), leg straightness, and hock burn (HB) were examined at day 33, and a latency-to-lie test was performed at day 34. At the end of the experiment (day 35), plasma, right leg, and litter samples were collected for mineral contents, meat quality, bone morphometric parameters, and litter quality assessments. The results indicated that probiotic-fed birds stood much longer during the latency-to-lie test with a greater tibial length, weight, and strength as well as higher plasma levels of calcium and phosphorus compared with the controls. In addition, probiotic-fed birds' leg muscle had higher color lightness at both 30 min and 5 h postmortem and greater water-holding capacity with a trend for less cooking loss (P = 0.056) and lower pH values (P < 0.05) at 5 h postmortem. Probiotic-fed birds' leg meat was tastier (P < 0.05) at 24 h after slaughter. These probiotic effects were greater in the 0.5X group than in the 0.25X group. There were no treatment effects on other measured parameters including gait score, HB, FPD, tibial lateral and medial wall thickness, diaphysis and medullary canal diameters, robusticity and tibiotarsal indexes, plasma magnesium concentrations, and litter moisture and pH values (P > 0.05). These findings indicate that the probiotic supplement could be a useful management tool for improving broiler production and welfare by enhanced bone mass and meat quality.

The elevation of ambient temperature beyond the thermoneutral zone leads to heat stress, which is a growing health and welfare issue for homeothermic animals aiming to maintain relatively constant reproducibility and survivability. Particularly, global warming over the past decades has resulted in more hot days with more intense, frequent, and long-lasting heat waves, resulting in a global surge in animals suffering from heat stress. Heat stress causes pathophysiological changes in animals, increasing stress sensitivity and immunosuppression, consequently leading to increased intestinal permeability (leaky gut) and related neuroinflammation. Probiotics, as well as prebiotics and synbiotics, have been used to prevent or reduce stress-induced negative effects on physiological and behavioral homeostasis in humans and various animals. The current data indicate dietary supplementation with a Bacillus subtilis-based probiotic has similar functions in poultry. This review highlights the recent findings on the effects of the probiotic Bacillus subtilis on skeletal health of broiler chickens exposed to heat stress. It provides insights to aid in the development of practical strategies for improving health and performance in poultry.

The aim of this study was to evaluate the effect of a synbiotic containing a probiotic (Enterococcus faecium, Pediococcus acidilactici, Bifidobacterium animalis, and Lactobacillus reuteri) and a prebiotic (fructooligosaccharides) on fear response, memory assessment, and selected stress indicators in broilers subjected to heat stress. A total of 360 1-day-old Ross 708 chicks were evenly divided among three treatments: a basal diet mixed with a synbiotic at 0 (G-C), 0.5 (G-0.5X), and 1.0 (G-1.0X) g/kg. After 15 d, the broilers were exposed to 32 °C for 9 h daily until 42 d. The object memory test was conducted at 15 day; touch, novel object, and isolation tests were conducted at 35 day; tonic immobility (TI) took place at 41 day. At 42 day, plasma corticosterone and tryptophan concentrations and heterophile/lymphocyte (H/L) ratios were measured. Compared to controls, synbiotic-fed broilers, regardless of concentration, had a shorter latency to make the first vocalization, with higher vocalization rates during the isolation test (p = 0.001). the G-1.0 group had the lowest H/L ratio (p = 0.001), but higher plasma tryptophan concentrations and a greater number of birds could reach the observer during the touch test (p = 0.001 and 0.043, respectively). The current results indicate that the synbiotic can be used as a growth promoter to reduce the fear response and stress state of heat-stressed broilers.

This study investigated the effect of different stocking density on behavior, body condition score and some blood parameters of male camels in the rut period. Thirty-six male dromedary camels in rut period weighing from 350 to 400 kg were randomly divided in to three stock densities, 3 [lower stocking density (75%) (LSD)], 4 [normal stocking density (100%)(NSD)], and 5 [higher stocking density (125%)(HSD)] camels on 60 m2 of pen, respectively. Behavioral observations were performed for 10 weeks once per week for posture, maintenance, aggressive and social behavior using instantaneous scan sampling. Blood samples were collected at the end of the experiment for some serum blood parameters (Total protein, Albumin, Globulin, and Albumin/Globulin ratio) and blood hormones (Cortisol, Testosterone, T3, T4, and T3/T4 ratio). The results indicated that, in comparison with LSD and NSD, HSD increased the aggressive behavior, standing duration and cortisol level (P < 0.05), while, it decreased the lying, walking, rumination, body condition score, testosterone, T3 and T4 level (P < 0.05). In addition, there were no significant effects on drinking behavior and blood parameters between all the treatments (P > 0.05). Conclusively, HSD in group rearing had a bad effect on aggression, body condition score and sexual performance of male camels in the rut period.

The objective of this study was to investigate the influences of zinc oxide nanoparticles (ZONPs) on the anxiety-related behaviors of male albino rats. Because of the sexual differences found in the anxiety related disorders, thirty-six male albino rats 40-days old weighed from 130 to 150 g and divided into three groups; group I served as a control, groups II and III were subjected to daily intraperitoneal injection of ZONPs (30 mg/kg or 60 mg/kg, respectively) for 5 days sequentially. Each treatment contained four replicates of 3 rats each. Eight rats per treatment (i.e.2 rats/replicate) were randomly taken and marked with green livestock spray for behavioral observation and anxiety testing on same day of injection. Elevated plus maize, open field, forced swimming, tail suspension tests were used for anxiety testing. Afterwards, the rats were sacrificed, and the histopathological evaluation of brain tissue was done. The results showed that the intraperitoneal injection of ZONPs reduced the standing behavior, climbing time of the forced swimming test, and increased the sleeping behavior, immobility time of the forced swimming test and agitation and immobility time of the tail suspension test (P < 0.05); while the ZONPs had no effects on alert activities, open field test, and elevated plus maize test (P > 0.05) in ZONPs injected groups. In addition, ZONPs induced necrosis of the nerve cells in cerebral cortex and the Purkinje cells in cerebellum.

The aim of this experiment was to examine the effect of different stocking densities on behavior, performance, and some blood parameters of Muscovy ducks. One hundred thirty-five-1-day old male Muscovy ducklings were divided in to 3 treatments with 5 replicates per treatment for a 60-day trial. Birds were housed at 6 birds per m2 (Control), 9 birds per m2 (Moderate stocking density) or 12 birds per m2 (High stocking density). The stocking density effects on duckling’s behavior, performance, and some blood parameters were investigated. At the end of the experiment, production and blood parameters were examined. The results showed that, stocking density birds exhibited less feeding, crouching, standing, walking and feather ruffling but more drinking, huddling, sitting, preening, feather pecking and wall pecking behaviors compared control ducklings (P < 0.05). The stocking density ducklings also had lower body weight, feed intake, body weight gain, eviscerated weight, dressing % compared to control birds (P < 0.05). At day 60, the serum calcium, phosphorus, total protein, thyroxine (T4) and total antioxidant of stocking density birds were lower, however, malondialdehyde and corticosterone were higher than that of control ducklings (P < 0.05), T3 and total albumin showed significant decrease only in high stocking density compared to control one (P < 0.05). These findings propose that rearing Muscovy ducks at 9 or 12 birds per m2 during fattening phase led to harmful influence on duck behaviors, performance, carcass characteristics and physiological parameters, with the potential to rear six birds on one square meter.