The effect of vitamin E, L-carnitine, and ginger on production traits, immune response, and antioxidant status in two broiler strains exposed to chronic heat stress

HSP90-regulated mitophagy can alleviate heat stress damage by inhibiting pyroptosis in the hepatocytes of Wenchang chickens

Heat shock protein 90 (HSP90) has a recognized anti-heat stress injury effect, but its function and corresponding molecular mechanism in heat-stressed hepatocytes are not fully understood, especially in tropical animals. In the present study, we identified several key factors affecting resistance to injury liver tissues from heat-stressed Wenchang chickens (a typical tropical species), such as HSP90, cellular pyroptosis and mitophagy. Heat stress upregulated the NLRP3/Caspase-1/GSDMD-N-mediated cellular pyroptosis pathway and the Pink1/Parkin-mediated mitophagy pathway in chicken hepatocytes, accompanied by the upregulation of HSP90. We also found that HSP90 overexpression significantly reduced heat stress-induced hepatocyte pyroptosis and enhanced mitophagy in primary hepatocytes from Wenchang chickens (PHWCs). HSP90 knockdown significantly increased heat stress-induced hepatocyte pyroptosis and decreased mitophagy in PHWCs. Interestingly, we performed immunoprecipitation and immunofluorescence colocalization and found that HSP90 and Pink1 can interact and directly regulate the level of mitophagy in PHWCs. Our results suggest that HSP90, which regulates Pink1, is an important factor in mitophagy that attenuates heat stress injury by inhibiting cellular pyroptosis.

Reduction of postweaning stress by fasting regimen and probiotics supplementation and study its effects on cecal microbiota and physiological parameters of growing rabbits

The aim of this work was to reduce the postweaning stress of growing rabbits by using fasting regimen and probiotic supplementation. Twenty-four weaned males new Zealand rabbits (5 weeks of age) were randomly divided into four equal groups including (1) rabbits fed ad labium diet served as control, (2) rabbits fasted for 12 h (two days/week) for 8 weeks, (3) rabbits fed ad labium diet with 2.0 cm3 probiotic/litter for 8 weeks, (4) rabbits fasted for 12 h (2 days/week) and take 2.0 cm3 probiotic/litter for 8 weeks. The probiotic inclusion corresponded to Bacillus subtilis and Bacillus licheniformis were supplemented to water in the probiotic groups. Results showed that food consumption was significantly higher (p < 0.01) in growing rabbits of ad libitum group (control group) compared to other in restricted rabbits, but body weight (BW) of growing rabbit in probiotic group at 6 and 12 week of age increased by12 and 19%, respectively, than other in control group and also improved daily weight gain (DWG) during all experimental periods. Compared with control, significant reductions (p < .01) in Plasma cholesterol, triglycerides, HDL, LDL, ALT, AST and urea were found in oral probiotic groups with or without fasting programme. Oral administration of probiotic without fasting regimen significantly improved all carcass characteristics compared to other groups. Total bacteria, fungi, coliforms and cellulolytic bacteria counts were significantly improved in the fasting group with or without adding probiotics compared to control group. Conclusively, using probiotics with or without fasting regimen for 8 weeks postweaning improved growth performance during fattening and enhancement cecum activity of growing rabbits.

Effects of emulsifier, betaine, and L-carnitine on growth performance, immune response, gut morphology, and nutrient digestibility in broiler chickens exposed to cyclic heat stress

1. This experiment investigated the efficacy of varying doses of an emulsifier blend (EB; 0 and 1 g/kg of diet), betaine (BT; 0 and 1 g/kg of diet) and L-carnitine (CT; 0 and 0.5 g/kg of diet) in broilers subjected to circular heat stress (HS) conditions. A total of 1080 one-day-old male broiler chickens (Ross 308) were randomly assigned to one of nine treatment groups (six pens/treatment with 20 birds/pen) according to a completely randomised design. The thermoneutral control broiler chickens were housed at a comfortable temperature and fed a standard diet (no additives). The other eight groups were exposed to cyclic HS conditions (34°C) for 8 h (10:00-18:00).2. There were EB × BT × CT interactions for body weight (BW) at 24 d (P = 0.038) and average daily gain (ADG) during the 10-24 d period (P = 0.049), with the greatest values found with concurrent supplementation of three supplements.3. Inclusion of EB resulted in greater (P < 0.05) BW, ADG, European performance index, uniformity rate, primary antibody titres against sheep red blood cells (SRBC), duodenal villus height (VH) and villus surface area, digestible energy (DE) and the coefficient of apparent ileal digestibility (CAID) of dry matter, crude protein, and fat However, feed conversion ratio, mortality rate and heterophile to lymphocyte ratio were lower (P < 0.05).4. Dietary BT supplementation improved (P < 0.05) all performance indicators, primary antibody titres against SRBC and Newcastle disease virus, serum total antioxidant capacity, duodenal VH, Jejunal VH/crypt depth and the CAID of dry matter and crude protein. The effect of dietary supplementation with CT was limited to an increase (P < 0.05) in ADG (d 10-24) and a decrease (P < 0.05) in serum malondialdehyde concentration (42 d) and jejunal crypt depth (42 d).5. In conclusion, dietary supplementation of either EB or BT alone or in combination ameliorated some of the detrimental effects of HS on growth performance, immunity and intestinal health in broilers, while a minor positive effect on performance and antioxidant status was observed with CT supplementation.

Effects of the dietary zinc source and vitamin E level on live weight and carcass yield and meat quality in male broilers reared under chronic cyclic heat stress conditions in the finisher phase

The objective of this study was to evaluate the effect of the interaction of the zinc source (ZnSO4 vs. zinc amino acid complex) and vitamin E level (50 IU/kg vs. 100 IU/kg) on meat yield and quality in broilers subjected to chronic cyclic heat stress in the finisher phase. A total of 1224 one-day-old male Ross 308 broilers were randomly distributed among four dietary treatments. Each treatment contained nine replicates of 34 birds, housed in floor pens in a temperature- and lighting-controlled room. Treatments were organized in a 2 × 2 factorial arrangement: two sources of zinc, 60 mg/kg of Zn as ZnSO4 or 60 mg/kg of Zn as zinc amino acid complexes (ZnAA), combined with two levels of vitamin E (50 or 100 IU/kg). From day 28 until day 37 (finisher phase), all birds were subjected to chronic cyclic heat stress (32 ± 2°C for 6 h daily). In the present study, it was observed that replacing ZnSO4 with ZnAA increased breast meat weight and yield of broilers reared under chronic cyclic heat stress conditions, whereas total slaughter yield was not affected. Moreover, it was observed that replacing ZnSO4 with ZnAA resulted in breast meat with a lower drip and thawing loss and a higher marinade uptake. In conclusion, replacing ZnSO4 with more readily available ZnAA can improve breast meat yield and increase the water-holding capacity of breast meat of broilers exposed to chronic cyclic heat stress at the end of the production cycle. However, as no thermoneutral group was included in the present study, the observed effects of the zinc source cannot be generalized as a solution for heat stress. Moreover, the beneficial effects of ZnAA on breast meat yield and quality seem to be independent of the vitamin E level, and increasing vitamin E level has no additional beneficial effects.

RETRACTED ARTICLE: Effects of emulsifier, betaine, and L-carnitine on growth performance, immune response, gut morphology, and nutrient digestibility in broiler chickens exposed to cyclic heat stress

1. This experiment investigated the efficiency of varying doses of an emulsifier blend (EB; 0 and 1 g/kg of diet), betaine (BT; 0 and 1 g/kg of diet) and L-carnitine (CT; 0 and 0.5 g/kg of diet) in broilers subjected to circular heat stress (HS) conditions.2. A total of 1080 one-day-old male broiler chickens (Ross 308) were randomly assigned to nine treatment groups (six pens/treatment with 20 birds/pen) in a completely randomised design. The thermoneutral control broiler chickens were housed at a comfortable temperature and fed a standard diet (no additives). The other 8 groups were exposed to cyclic HS conditions (34°C) for 8 h (10:00-18:00).3. There were EB × BT × CT interactions for body weight (BW) at 24 d (P=0.038) and average daily gain (ADG) during the 10-24 d period (P=0.049), with the greatest values with concurrent supplementation of all three ingredients.4. Inclusion of EB resulted in greater (P<0.05) BW, ADG, European performance index, uniformity rate, primary antibody titres against sheep red blood cells (SRBC), duodenal villus height (VH) and villus surface area, nitrogen-corrected apparent metabolisable energy (AMEn) and apparent ileal digestibility (AID) of dry matter, crude protein and fat, but lower (P<0.05) feed conversion ratio, mortality rate and heterophile to lymphocyte ratio.5. Dietary BT supplementation improved (P<0.05) overall performance indicators, primary antibody titres against SRBC and Newcastle disease virus, serum total antioxidant capacity, duodenal VH, Jejunal VH/crypt depth, AID of dry matter and crude protein. The effect of dietary supplementation with CT was limited to an increase (P<0.05) in ADG (d 10-24) and a decrease (P<0.05) in serum malondialdehyde concentration (42 d) and jejunal crypt depth (42 d).6. In conclusion, dietary supplementation of either EB or BT alone or in combination can ameliorate some of the detrimental effects of HS on growth performance, immunity and intestinal health in broilers, while a minor positive effect on performance and antioxidant status was observed with CT supplementation.

Influence of dietary L-carnitine and lysine-methionine levels on reproductive performance and blood metabolic constituents of breeder ducks

The present study aimed to evaluate the influence of dietary supplementation of different levels of L-carnitine and/or lysine-methionine (Lys-Met) on reproductive performance of breeder ducks. Three L-carnitine (0, 75 and 150 mg/kg) and three lysine-methionine (100%, 110% and 120% above the NRC (Nutrient requirements of poultry, 1994, National Academy Press) recommendations) levels were fed to 180 breeder ducks (144 females and 36 males) in a completely randomized design for 49 days. Laying performance and reproductive traits were evaluated; additionally, uric acid, total protein total, triglycerides, total cholesterol, low-density lipoprotein, high-density lipoprotein, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were assessed. The Lys-Met above 100% NRC (Nutrient requirements of poultry, 1994, National Academy Press) recommendations with or without L-carnitine improved feed utilization (p < .05). Furthermore, Lys-Met above 100% recommendations without L-carnitine improved egg fertility and hatchability. Fertility and hatchability improved in breeders fed on L-carnitine with 120% Lys-Met (p < .05). Serum glucose increased and total cholesterol reduced on 100% Ly-Met without L-carnitine or 110% Ly-Met with 150 mg L-carnitine (p < .05). Glucose was reduced, while total cholesterol increased on 75 mg L-carnitine and 100% Lys-Met (p < .05). Increasing Lys-Met without L-carnitine reduced serum protein (p < .05). Albumin and ALT increased on 75 mg L-carnitine-100% Lys-Met and reduced on 150 mg L-carnitine-120% Lys-Met (p < .05). There were no interaction effects on globulin, uric acid and AST (p > .05). Thus, based on findings, breeder ducks responded to dietary Lys-Met more efficiently than L-carnitine; however, more research is needed to evaluate also economic aspects related to L-carnitine dietary supplementation.

Phytogenic Feed Additives in Poultry: Achievements, Prospective and Challenges

Simple Summary

Plant secondary metabolites and essential oils also known as phytogenics are biologically active compounds that have recently attracted increased interest as feed additives in poultry production, due to their ability to promote feed efficiency by enhancing the production of digestive secretions and nutrient absorption, reduce pathogenic load in the gut, exert antioxidant properties and decrease the microbial burden on the animal’s immune status. However, the mechanisms are far from being fully elucidated. Better understanding the interaction of phytogenics with gastrointestinal function and health as well as other feed ingredients/additives is crucial to design potentially cost-effective blends.

Abstract

Phytogenic feed additives have been largely tested in poultry production with the aim to identify their effects on the gastrointestinal function and health, and their implications on the birds’ systemic health and welfare, the production efficiency of flocks, food safety, and environmental impact. These feed additives originating from plants, and consisting of herbs, spices, fruit, and other plant parts, include many different bioactive ingredients. Reviewing published documents about the supplementation of phytogenic feed additives reveals contradictory results regarding their effectiveness in poultry production. This indicates that more effort is still needed to determine the appropriate inclusion levels and fully elucidate their mode of actions. In this frame, this review aimed to sum up the current trends in the use of phytogenic feed additives in poultry with a special focus on their interaction with gut ecosystem, gut function, in vivo oxidative status and immune system as well as other feed additives, especially organic acids.

Evaluation of unprotected and rumen-protected L-carnitine in vitro and in vivo

This study aimed to evaluate the effectiveness of unprotected and rumen-protected L-carnitine through in vitro tests, rumen degradation tests, and in vivo tests. Twelve rumen-fistulated crossbred rams with similar body weights of 55 ± 3.6 kg and ages of 3 ± 0.2 yr old were divided into three treatment groups in a 3 × 3 Latin square design, G1 (basal diet with no additives), G2 (unprotected L-carnitine), or G3 (rumen-protected L-carnitine). Ruminal fluid and blood samples were collected before morning feeding on the last day of each experimental period (21 d). The percentage of L-carnitine remaining in the simulated rumen and abomasum and rumen increased with the increase in the wall material ratio (P < 0.05). L-carnitine supplementation decreased the plasma urea nitrogen concentration in the sheep (P < 0.05). G3 resulted in higher glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities as well as higher total antioxidant capacity (T-AOC) and lower malondialdehyde (MDA) concentrations in plasma than G1, and the difference was significant among the groups (P < 0.01). Thus, L-carnitine in the rumen could be protected by encapsulation for a certain time. Unprotected and rumen-protected L-carnitine supplementation effectively enhanced the antioxidant capacity of sheep, and the antioxidant capacity of sheep supplemented with rumen-protected L-carnitine was higher than that of sheep supplemented with unprotected L-carnitine.

Effect of L-Carnitine and/or Calf Thymus Gland Extract Supplementation on Immunity, Antioxidant, Duodenal Histomorphometric, Growth, and Economic Performance of Japanese Quail (Coturnix coturnix japonica)

This study aimed to evaluate the supplementation (of drinking water) effects of L-Carnitine (LC) and/or calf thymus extract (TE) on immunity, antioxidant, duodenal histomorphometric, growth, and economic performance of Japanese quail. Six hundred, one day old unsexed quail were divided into four groups, the control group (G1) received plain drinking water, while G2, G3, and G4 were supplemented with LC and/or TE, respectively. The treated groups recorded a significant (p < 0.05) improvement in the final body weight, weight gain, feed conversion ratio, phagocytic activity %, phagocytic index, lymphocytes %, and plasma glutathione level compared to the G1. On the other hand, these supplementations significantly lower the mortality rate %, heterophil %, H/L ratio and plasma malondialdehyde level of the supplemented groups relative to G1. The supplemented groups recorded a non-significant increase in duodenal histomorphometric parameters (villous height, villous width, surface area, and crypt depth) relative to G1. Generally, LC and/or TE improve the values of economic profile (total returns, net profit, total return/total costs %, etc.) in treated groups compared to the control one. In conclusion, L-carnitine supplementation was more effective than TE or their combination with TE in the immunological, anti-oxidative, growth, and economic performance.

Dietary supplementary glutamine and L-carnitine enhanced the anti-cold stress of Arbor Acres broilers

Newborn poultry in cold regions often suffer from cold stress, causing a series of changes in their physiology and metabolism, leading to slow growth and decreased production performance. However, a single anti-stress substance cannot completely or maximally eliminate or alleviate the various effects of cold stress on animals. Therefore, the effects of the supplemented glutamine and L-carnitine on broilers under low temperature were evaluated in this study. Broilers were randomly allocated into 16 groups which were respectively fed with different levels of glutamine and L-carnitine according to the L16 (45) orthogonal experimental design for 3 weeks (the first week is the adaptive feeding period; the second and third weeks are the cold exposure period). Growth performance was recorded, and blood samples were collected during cold exposure. The results showed the supplementation had altered the plasma parameters, growth performance and cold-induced oxidative stress. The increase of corticosterone and suppression of thyroid hormone was ameliorated. Supplemented groups had lower daily feed intake and feed-to-gain ratio, higher daily weight gain and better relative weights of immune organs. Plasma glucose, total protein, blood urea nitrogen and alkaline phosphatase changed as well. Oxidative stress was mollified due to the improved activities of superoxide dismutase and glutathione peroxidase, heightened total antioxidant capacity and stable malondialdehyde. Dietary glutamine and L-carnitine improve the growth performance, nutritional status and cold stress response of broilers at low temperature, and their interaction occurred.

Alpha-tocopherol acetate and alpha lipoic acid may mitigate the development of wooden breast myopathy in broilers at an early age

1. The objective of this study was to identify the effects of the antioxidant alpha-tocopherol acetate (ATA) and alpha lipoic acid (ALA) which have anti-inflammatory effects on developmental onset, severity and the progression of wooden breast (WB) based on Pectoralis major (P. major) muscle morphology and expression of genes associated with WB during the first three weeks post-hatch.2. A total of 160 newly hatched Ross 708 broiler chicks were randomly assigned in a replicated trial to either a control group or three dietary treatments (ATA 160 mg/kg feed, ALA 500 mg/kg feed or in combination).3. Microscopic changes associated with WB began at one week of age in all groups. The ATA acetate and ALA fed in combination decreased WB severity at two weeks of age (P = 0.05) and ATA alone or in combination reduced severity at three weeks of age compared to the control group (P = 0.05). Expression of myogenic determination factor 1 and peroxisome proliferator-activated receptor gamma was reduced in all dietary treatments compared to the control at three weeks of age (P ≤ 0.05), which suggested reduced muscle degeneration and lipid deposition.4. ATA and ALA fed both independently and in combination had a positive effect on mitigating WB severity microscopically as early as two weeks of age.

Effect of Supplementation of Fermented Yeast Culture on Hormones and Their Receptors on Exposure to Higher Temperature and on Production Performance after Exposure in Nicobari Chickens

Heat stress (HS) affects the production performance in chickens and causes economic loss to the producers. Most of the studies have been conducted on and for the welfare of broilers. We still lack information on the physiological parameters being affected during chronic heat stress in layers. To fill this gap, the present study evaluated the effect of heat stress (induced in the chamber) during the prelaying period (21-23 weeks) on plasma levels of the hormones leptin and ghrelin and GH and expression of the respective receptors and heat stress markers. Three groups were considered, one at room temperature (CR) and the other two groups (SH and CH) subjected to heat stress at 39°C for four hours for three weeks (21-23 weeks of age). The SH group (SH) feed was supplemented with fermented yeast culture (FYC, 700 mg/kg), whereas the CH group was devoid of it. After that, all the groups were shifted to shed under natural ambient conditions till 31 weeks of age. Studies were restricted to production performance only. Feed offered without yeast culture (CH group) had a smaller concentration of plasma hormones (P < 0.01) and increased expression fold of the hormone receptors (P < 0.01). Further, the group also presented higher liver AMP kinase enzyme, plasma MDA (malondialdehyde), and cholesterol concentrations. These changes likely explained the decrease in feed intake and the CH group's body weight and further reduced the production performance during the laying period. Supplementation with FYC to birds had an opposite effect on the above-mentioned parameters, reducing HS effects. In summary, supplementation with FYC (700 mg/kg) maintained physiological parameters as in the CR group under HS conditions and negated adverse effects on parameters both before and during laying periods.

Effect of vitamin E level and dietary zinc source on performance and intestinal health parameters in male broilers exposed to a temperature challenge in the finisher period

The objective of this study was to evaluate the interaction of zinc source (ZnSO₄ vs. zinc amino acid complex) and vitamin E level (50 IU vs. 100 IU) on performance and intestinal health of broilers exposed to a temperature challenge in the finisher period. A total of 1224 day old male Ross 308 broilers were randomly distributed among 4 dietary treatments (9 replicates per treatment). Dietary treatments were organized in a 2 × 2 factorial arrangement: two sources of zinc, 60 mg/kg of Zn as ZnSO₄ .7H₂ O or 60 mg/kg of Zn as zinc amino acid complexes (ZnAA) combined with two levels of vitamin E (50 or 100 IU/kg). Zinc and vitamin E were added to a wheat/rye-based diet that was designed to create a mild nutritional challenge. From day 28 until day 36 (finisher period), all birds were subjected to chronic cyclic high temperatures (32°C ± 2°C and RH 55-65% for 6 h daily). The combination of ZnAA and 50 IU/kg of vitamin E improved weight gain in the starter (day 0-10), finisher (day 28-36) and overall period (day 0-36) and feed conversion ratio in the starter (day 0-10) and finisher phase (day 28-36). Providing Zn as ZnAA significantly improved villus length and villus/crypt ratio in the starter, grower and finisher period and decreased infiltration of T-lymphocytes and ovotransferrin leakage in the finisher period. In conclusion, providing broilers with a diet supplemented with ZnAA and a vitamin E level of 50 IU/kg, resulted in better growth performance as compared to all other dietary treatments. Interestingly, under the conditions of this study, positive effects of ZnAA on performance did not occur when vitamin E was supplemented at 100 IU/kg in feed. Moreover, providing zinc as zinc amino acid complex improved intestinal health.

Evaluation of physiological and molecular responses to acute heat stress in two chicken breeds

High environmental temperatures are a foremost concern affecting poultry production; thus, understanding and controlling such conditions are vital to successful production and welfare of poultry. In view of this, a completely randomized design with a 2 × 2 factorial arrangement involving two local strains (Kirin chicken (KC) and Three-yellow chicken (TYC)) and two temperature groups (normal/control = 30 ± 2 °C and acute heat stress (AHS) = 35 ± 1 °C for 8-h with 70% humidity) was used to assess the main regulatory factors such as heat shock protein (HSP70) gene, cytokine genes (IL-1β, IL-6, IL-10), muscle development gene (IGF-1) and tissue histopathological changes. At 56 days old, the temperatures of the comb (CT), feet (FT), eyelid (ET) and rectal (RT) from each group were taken thrice at 0, 2, 4 and 8-h during AHS, and 1 and 3-h recovery period after AHS. At 80 days old, the slaughter weight was also analyzed. The CT and ET of the AHS groups increased during the 8-h trial, while the RT of both strains decreased significantly at 4 h but increased at 8 h in the TYC group. All temperature recordings dropped in the AHS groups of both strains during the recovery period. The results revealed that the mRNA expression of HSP70 in the liver was higher in the heat-stressed group of both strains compared to the control. The expression of HSP70 was shown in the AHS-KC group to be significantly high compared to the control (P < 0.05). Moreover, the IGF1 gene in the liver, breast muscle and leg muscle was downregulated in the AHS-TYC group compared to the control (P < 0.05), although that in the AHS-KC was downregulated in the breast muscle. The mRNA expression of spleen IL-1β significantly decreased in the AHS-TYC group (P < 0.01), whereas that of the AHS-KC had no significant difference (P > 0.05). The mRNA expression of spleen IL-6 and IL-10 was increased in the AHS-KC group but did not exhibit obvious changes in the AHS-TYC. Correspondingly, the histopathological examinations revealed tissue injury in the AHS groups of both strains, with the TYC strain experiencing more severe changes. The final live and carcass weights showed a significant enhancement in the treatments (P < 0.01 and P < 0.05, respectively) and treatment×strain interaction (P < 0.05) with breast muscle rate significantly reducing among the treatments (P < 0.01) at 80 days. In conclusion, the differential response to AHS after physiological, molecular and immune response portrays KC to have better thermal tolerance than the TYC.

Effect of dietary supplementation of wildCumin (Bunium persicum) seeds on performance, nutrient digestibility and circulating metabolites in broiler chicks during the finisher phase

The objective of the present study was to evaluate the impact of inclusion of wild cumin seeds (WCS) on performance, nutrient digestibility and blood profile in broilers during the finisher phase. For this purpose, 360, 14 days old chicks were randomly divided into four groups designated as CONT (control), 0.5WCS, 1.0WCS and 1.5WCS with 5 replicates, which were supplemented with WCS at the rate of 0, 0.5, 1, and 1.5% respectively. On the overall, feed intake was significantly (p < 0.01) higher in the CONT compared to the 1.0WCS. At the end of the finisher phase, and overall basis, body weight and feed conversion ratio were significantly (p < 0.05) higher in 0.5WCS. Crude protein apparent digestibility in the ileum was significantly (p < 0.05) higher in 0.5WCS compared to the CONT, while crude fat digestibility was significantly (p < 0.01) higher in 0.5WCS and 1.5WCS compared to the control. Similarly, serum triglyceride was significantly (p < 0.05) lower in 0.5WC but high density lipoprotein was significantly (p < 0.05) higher in the same group. It was concluded that wild Cumin at the rate of 0.5% was superior compared to the other treatments in the diet to improve the performance, nutrient digestibility and blood metabolites in broiler during the finisher phase.

Protective effects of dietary mannan oligosaccharide on heat stress-induced hepatic damage in broilers

Heat stress is a major concern in broiler's production, which can damage liver of broilers. This study investigated the protective effects of mannan oligosaccharide (MOS) on heat stress-induced hepatic injury in broilers. A total of 144 day-old male chicks were allocated into three treatment groups. Broilers raised under normal ambient temperature were fed a basal diet (control group), and broilers under heat stress (32-33 °C for 8 h daily) were given the basal diet supplemented without MOS (heat stress group) or with 1 g/kg MOS (MOS group) for 42 days. Compared with the control group, heat stress reduced liver weight, whereas increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in the serum. It also reduced glutathione peroxidase (GSH-Px) activity in the serum and liver, GSH content, and superoxide dismutase (SOD) activity in the liver, but increased malondialdehyde (MDA) concentration in the serum and liver. Dietary MOS decreased serum ALT activity in heat-stressed broilers. MOS inclusion also decreased serum MDA content, but elevated hepatic GSH-Px and SOD activities, with MDA content and GSH-Px activity still being different from the control group, and SOD activity being similar to the control group. Heat stress increased concentrations of tumor necrosis factor α (TNF-α) in the serum and liver, interleukin-1β (IL-1β) in the liver, and mRNA abundances of HSP70, TLR4, MyD88, TNF-α, and IL-1β in the liver of broilers. Serum TNF-α content and mRNA abundances of hepatic TLR4 and TNF-α in MOS group were lower than the heat stress group, whereas these indexes were still higher than the control group. Our results indicated that dietary MOS ameliorated hepatic damage in heat-stressed broilers through alleviation of oxidative stress and inflammation.

Effects of gingerols-rich extract of ginger on growth performance, serum metabolites, meat quality and antioxidant activity of heat-stressed broilers

In order to investigate the effects of dietary ginger extract (GE) enriched in gingerols on broilers under heat stress (HS) from 21 to 42 days of age, a total of 144 Ross 308 male broilers were randomly allocated to three groups with six replicates of eight broilers per replicate. Broilers in the control group were raised at 22 °C and fed a basal diet, and broilers in the other two groups were raised under cyclic HS (34 °C from 9:00 to 17:00 and at 22 °C for the rest of the time) and fed the basal diet with or without 1000 mg/kg GE. Supplementation of GE improved (P < 0.05) final body weight, average daily gain and feed conversion ratio of broilers under HS, and tended (P < 0.1) to increase breast muscle yield. The alterations of serum total protein, albumin, total cholesterol levels and aspartate aminotransferase activity under HS were reversed (P < 0.05) by GE, which also decreased (P < 0.05) serum triglyceride level and alanine aminotransferase activity. The decreased redness (a* value) and increased drip loss of breast muscle induced by HS were restored (P < 0.05) by GE. Moreover, GE supplementation increased (P < 0.05) total antioxidant capacity and decreased (P < 0.05) malondialdehyde content in liver and breast muscle, and increased (P < 0.05) glutathione peroxidase activity in serum and breast muscle. In conclusion, dietary GE supplementation restored growth performance, serum metabolites and meat quality of broilers under HS possibly by improving antioxidant activity.

Dietary supplementation of milk thistle (Silybum marianum): growth performance, oxidative stress, and immune response in natural summer stressed broilers

The aim of the study was to investigate the influence of dietary supplementation of various levels of milk thistle (MT) on growth performance, oxidative stress, and immune response of natural summer stressed broilers. A total of 120 1-day old broiler chicks were distributed into 4 treatments: MT-0 (control), MT-5 (5 g/kg of MT), MT-10 (10 g/kg of MT), and MT-15 (15 g/kg of MT), each with 3 replicates having 10 birds per replicate. Results showed that overall feed intake, body weight, feed conversion ratio (FCR), and dressing percentage were significantly (P < 0.5) higher with MT-15 as compared with the other experimental treatments. Unlikely, significantly lower level of malondialdehyde (MDA) was observed with MT-15. Dietary supplementation of MT had no significant effect on paraoxonase activity in broiler. Antibody titer was significantly (P < 0.05) higher with MT-15 while it was lower with the control treatment. It was concluded that dietary supplementation of MT at the rate of 15 g/kg can significantly lower the negative effects of natural summer stressed broilers.

Comparative effects of Bacillus subtilis and Bacillus licheniformis on live performance, blood metabolites and intestinal features in broiler inoculated with Salmonella infection during the finisher phase

Free of Salmonella infection, a total of 300 broiler chicks (Ross 308) were randomly allotted to six dietary treatments (10 replicates) as follows: Negative control (only the basal diet); positive control (infected only); T1, infection + antibiotic (avilamycin); T2, infection + Bacillus subtilis and T3, Salmonella infection + Bacillus licheniformis. The results revealed that production performance was severely affected in the infected group. Also the supplementation of Bacillus subtilis (T2) significantly (P < 0.01) improved feed intake, body weight and performance efficiency factor as compared to the positive control. In addition, feed conversion ratio was significantly (P < 0.01) improved in T2 and T3 compared to the positive control. The results of intestinal health showed that significantly (P < 0.01) higher villus height and total surface area were found in T2 compared to positive control. The results of blood cholesterol, glucose, globulin and total protein concentration were significantly (P < 0.05) higher in T3 compared to the infected birds (positive control). It was concluded that Bacillus subtilis produced superior results in comparison with Bacillus licheniformis in term of growth and intestinal features in broiler by mitigating the deleterious effects of Salmonella infection.

Zinc source modulates zootechnical characteristics, intestinal features, humoral response, and paraoxonase (PON1) activity in broilers

The current experiment was performed to find the potential effect of inorganic and organic forms of zinc (Zn) on growth, intestinal histomorphology, immune response, and paraoxonase (PON1) activity in broiler. In this experiment, a total of 450 broiler chickens were assigned to four experimental and control groups. The birds received organic Zn at the rate of 50 mg/kg (OZ-50) and 60 mg/kg (OZ-60) or inorganic Zn at the rate of 50 mg/kg (IZ-50) and 60 mg/kg (IZ-60) for an experimental period of 30 days. Significantly (P < 0.05) higher feed consumption, body weight, feed conversion ratio, and production efficiency factor (PEF) were recorded in OZ-50. Similarly, antibody titer against infectious bronchitis (IB) and PON1 activity was higher (P < 0.05) in OZ-50 compared with the control group. In addition, significantly (P < 0.05) higher villus dimensions and goblet cell count were recorded for the group OZ-50 compared with other treatments. It was concluded that the organic form of Zn was superior in improving the growth, histological features of intestines, humoral response, and PON1 activity in broiler.

Basic mechanisms of the regulation of L-carnitine status in monogastrics and efficacy of L-carnitine as a feed additive in pigs and poultry

A great number of studies have investigated the potential of L-carnitine as feed additive to improve performance of different monogastric and ruminant livestock species, with, however, discrepant outcomes. In order to understand the reasons for these discrepant outcomes, it is important to consider the determinants of L-carnitine status and how L-carnitine status is regulated in the animal's body. While it is a long-known fact that L-carnitine is endogenously biosynthesized in certain tissues, it was only recently recognized that critical determinants of L-carnitine status, such as intestinal L-carnitine absorption, tissue L-carnitine uptake, endogenous L-carnitine synthesis and renal L-carnitine reabsorption, are regulated by specific nutrient sensing nuclear receptors. This review aims to give a more in-depth understanding of the basic mechanisms of the regulation of L-carnitine status in monogastrics taking into account the most recent evidence on nutrient sensing nuclear receptors and evaluates the efficacy of L-carnitine as feed additive in monogastric livestock by providing an up-to-date overview about studies with L-carnitine supplementation in pigs and poultry.

Osmoregulatory function of betaine in alleviating heat stress in poultry

This review focuses on the osmoregulatory function of betaine and its effect in terms of alleviating heat stress in poultry. Poultry appear to be particularly sensitive to temperature-associated environmental challenges, especially heat stress. High ambient temperatures are deleterious to productive performance in poultry, including broilers, laying hens, quails and turkeys, resulting in considerable economic losses. Heat stress impairs overall poultry production by decreasing feed intake and negatively affecting intestinal development, leading to reduced nutrient digestibility. Apart from inducing a high mortality rate, heat stress is known to depress growth rate and reduce meat yield in broilers. In layers, lower feed intake impairs ovarian function, leading to decreased feed efficiency, egg production and egg quality. In addition, reduced immune functions, such as thyroid activity and antibody production, are evident in poultry exposed to heat stress. Heat stress increases the production of oxidants, causing oxidative stress and lipid peroxidation of cell membranes. Poultry respond physiologically and behaviourally when encountering the negative effects of heat stress, attempting to return the body to homeostasis. This requires energy at the expense of weight gain or egg production. Due to its zwitterionic structure, betaine has osmoprotective properties that aid in protecting intestinal cell proteins and enzymes from environmental stress, including high ambient temperature, thereby counteracting performance losses. Betaine also exerts an osmoregulatory role in cells, regulating water balance, and this results in more stable tissue metabolism. Inclusion of betaine in the diet may be beneficial for alleviating physical reactions to heat stress, as indicated by increases in nutrient digestibility. In broilers, betaine supplementation increases weight gain and breast muscle yield, while improving feed conversion. In layers, betaine supplementation improves egg production, egg quality traits and immune indices. In conclusion, due to its osmoregulatory functions, betaine plays an important role in alleviating heat stress in poultry.

Supplementing dietary rosemary (Rosmarinus officinalis L.) powder and vitamin E in broiler chickens: evaluation of humoral immune response, lymphoid organs, and blood proteins

The aim of the present study was to evaluate the effect rosemary (Rosmarinus officinalis L.) powder (RP) and vitamin E (VE) at different levels on humoral immunity of broilers during a 42-day production cycle. A total of 270 1-day-old male chicks were assigned to nine groups with three replicates of ten birds each, and diets were supplemented with 0, 0.5, or 1.0% RP and 0, 100, or 200 mg/kg VE, respectively. Commercial-inactivated vaccines against avian influenza (AI) and Newcastle disease (ND) viruses, and living infectious bronchitis virus (IBV) vaccine were administered by spray method. Sheep red blood cells (SRBC) were administered subcutaneously. Blood samples were collected from birds 1 week after each vaccination to determine antibody titers. At the 42nd day, blood samples were also assessed for globulin level, and lymphoid tissues (thymus, spleen, and bursa) were weighed. Neither antibody titers against viruses nor lymphoid tissues weight were affected by RP and/or VE (P > 0.05) treatments. However, broilers supplemented with 0 mg/kg of VE had lower antibody titers against SRBC than those fed 100 mg/kg of VE (P < 0.05) at the 24th day. A significant RP × VE interaction effect (P < 0.05) on plasma globulin level was observed. The findings of our study suggest that dietary RP and VE additives can interact and modulate the humoral immunity of broilers, but not sufficiently to improve antibody titers against specific virus during a 42-day production cycle.