The Influence of a Nanoemulsion of Cardamom Essential Oil on the Growth Performance, Feed Utilization, Carcass Characteristics, and Health Status of Growing Rabbits under a High Ambient Temperature

Recently, nanotechnology approaches have been employed to enhance the solubility, availability, and efficacy of phytochemicals, overcoming some industrial obstacles and natural biological barriers. In this regard, 120 clinically healthy growing V-line rabbits (5 weeks old) reared during the summer season were divided randomly into four equal experimental groups (30 rabbits each). The first group received a basal diet without the supplementation of the nanoemulsion of cardamom essential oil (NCEO) (0 g/kg diet) and served as a control (NCEO 0). The other groups were given diets containing NCEO at levels of 150 (NCEO 150), 300 (NCEO 300), and 600 (NCEO 600) mg/kg diet, respectively. The growth performance (higher LBW and ADG), feed utilization (lower FCR), dressing percentage, and relative weight of the liver were improved significantly in the NCEO-treated groups compared to the control group. Moreover, the dietary treatment significantly decreased the rectum temperature and respiration rate, minimizing the 350 and 325 mg NECO/kg diets. The erythrocyte count, hematocrit, and hemoglobin concentration were significantly increased (p < 0.05), while white blood cells were significantly diminished (p = 0.0200) in the NCEO300 and NCEO600 groups compared to the control group. Treatment with 300 or 600 mg NCEO/kg significantly increased the blood serum total protein and albumin compared to the control group. Meanwhile, the liver enzymes (AST and ALT), uric acid, and creatinine concentrations decreased significantly in the NCEO300 group compared to the control group. The concentrations of triglycerides and total cholesterol were reduced significantly by the dietary treatment. The total antioxidant capacity, dismutase activity, and glutathione concentration were significantly higher, while the malondialdehyde and protein carbonyl levels were significantly lower in the NCEO300 group than in the control. The inflammatory responses and immunity statuses were improved in the blood serum of the NCEO-treated rabbits compared to the control. Heat-stress-induced pathological perturbations in renal/hepatic tissues and NCEO co-treatment successfully re-established and recovered near-control renal-hepatic morphology. In conclusion, a dietary supplementation of NCEO (300 mg/kg) could effectively enhance growing rabbits' growth indices, feed efficiency, redox balance, immunity, and inflammatory responses during the summer.

Efficacy of a phytonutrient supplement at different dietary protein contents on growth performance, gut morphology, digestive enzymes activities and stress indicators of broilers subjected to circular heat stress

Context Dietary manipulations such as reductions in protein or the addition of bioactive feed additives might alleviate the adverse effects of high ambient temperature in poultry. Aims The effects of dietary crude protein (CP) and phytonutrient mixture (PM) on growth performance and physiological responses were evaluated in broilers under circular heat stress (HS). Methods In total, 420 1-day-old broiler chickens were randomly distributed to seven treatments in a factorial arrangement (3 × 2), with three levels of CP (normal, medium (95% of the normal CP content) and low (90% of the normal CP content)) and with or without the addition of PM (mixture of 5 mg/kg carvacrol, 3 mg/kg cinnamaldehyde, and 2 mg/kg capsicum oleoresin). The thermoneutral control (TNC) birds were housed in a thermoneutral chamber and fed with a normal-CP diet without PM supplementation. The other six groups were kept in a HS chamber (33°C) for 8 h (1000 hours to 1800 hours). Key results After 6 weeks, feeding broiler chickens with low-CP diets had adversely affected growth performance and intestinal protease activities, while mortality rate, heterophile to lymphocyte ratio, and serum cortisol concentration of the low-CP group were lower (P &lt; 0.05) than those of the high-CP group. Dietary PM supplementation also positively influenced (P &lt; 0.05) average daily gain, feed conversion ratio, intestinal lipase and trypsin activities and serum T4 concentration. There were the CP × PM interactions (P &lt; 0.05) for jejunal villus height and villus surface area, indicating that the effect of PM on these responses was more marked at the lower dietary CP contents. Conclusions Supplementation with PM can ameliorate the detrimental effects of HS on productive performance and digestive enzyme activities in broilers. The PM supplementation could improve intestinal morphology when applied to the diets of heat-stressed broilers with lower CP contents (95% and 90% of the recommendations). Implications Although growth performance was reduced by feeding low-CP diets (90% of the normal CP content), a beneficial effect was observed on the stress indicators of broilers grown in HS conditions. Dietary supplementation of PM might also be an effective strategy to alleviate the adverse effect of HS.

Spontaneous Intake and Long-Term Effects of Essential Oils After a Negative Postnatal Experience in Chicks

The postnatal period is critical for broiler chicks as they are exposed to potentially stressful environmental changes in the hatchery and during transportation to the rearing houses. The ability of broiler chicks to spontaneously drink essential oils (EO) to mitigate the effects of a negative postnatal experience was tested. Chicks were placed in the rearing facility either immediately (C group), or after a 24 h-delay period (D group) to mimic a delay in transportation possible under commercial conditions. In experiment 1, each group had access to either water only or to water and one EO (cardamom, marjoram, or verbena) from D1 to D13. Verbena EO intake was higher in the D group than in the C group from D1 to D6 and cardamom EO intake was lower in the D group than in the C group from D6 to D13. In experiment 2, half of the groups had access to water only and the other half had both water and the three EO simultaneously. Chicks from D and C groups chose the EO similarly except for cardamom EO with a lower intake being observed in the D than in the C group from D6 to D12. The delayed placement of the D group reduced chicken growth until 34 days of age and temporarily increased the feed conversion ratio, but did not affect their welfare or the prevalence of health disorders. The EO intake did not mitigate the growth reduction in D group chicks, but did mitigate the reduced Pectoralis major muscle yield. In conclusion, chicks were able to make spontaneous choices regarding EO intake according to their postnatal experience when EO were presented individually, but not when presented simultaneously as in our experimental design. The EO intake only partially mitigated the decrease in chicken performance after the negative postnatal experience.

Evaluation of Aloe vera and synbiotic as antibiotic growth promoter substitutions on performance, gut morphology, immune responses and blood constitutes of broiler chickens

This study was performed to investigate the effect of dietary supplementation with Aloe vera (AV) powder and synbiotic as growth promoter agents on performance, gut morphology, immune responses, hematology and serum biochemistry in broilers. A total of 240-day-old male broiler chicks (Ross 308) were randomly assigned to six treatments with four replicates. Birds were offered either a corn-soybean meal basal diet (control) or the basal diet supplemented with 200 mg/kg virginiamycin (VM), 1 g/kg synbiotic (Syn), 2.5 g/kg AV (AV1), 5.0 g/kg AV (AV2) or 7.5 g/kg AV (AV3). Chickens fed any of the diets, except diet AV1, exhibited better feed conversion ratios at the 14-28 day period and higher average daily gain and duodenal villus height/crypt depth ratio at 42 days than those fed the control diet. Synbiotic supplementation caused a marked increase in the serum antibody titer against infectious bursal disease and infectious bronchitis vaccines. Feeding diet AV3 significantly increased red blood cell count and hemoglobin concentration, and decreased serum triglyceride level compared to the control group. The results suggested that dietary inclusion of 5 and 7.5 g/kg AV, similar with synbiotic supplementation, can be applied as effective alternatives to in-feed antibiotics for broiler diets.