Alleviating heat stress effects in poultry: updates on methods and mechanisms of actions

Heat stress is a threat that can lead to significant financial losses in the production of poultry in the world’s tropical and arid regions. The degree of heat stress (mild, moderate, severe) experienced by poultry depends mainly on thermal radiation, humidity, the animal’s thermoregulatory ability, metabolic rate, age, intensity, and duration of the heat stress. Contemporary commercial broiler chickens have a rapid metabolism, which makes them produce higher heat and be prone to heat stress. The negative effect of heat stress on poultry birds’ physiology, health, production, welfare, and behaviors are reviewed in detail in this work. The appropriate mitigation strategies for heat stress in poultry are equally explored in this review. Interestingly, each of these strategies finds its applicability at different stages of a poultry’s lifecycle. For instance, gene mapping prior to breeding and genetic selection during breeding are promising tools for developing heat-resistant breeds. Thermal conditioning during embryonic development or early life enhances the ability of birds to tolerate heat during their adult life. Nutritional management such as dietary manipulations, nighttime feeding, and wet feeding often, applied with timely and effective correction of environmental conditions have been proven to ameliorate the effect of heat stress in chicks and adult birds. As long as the climatic crises persist, heat stress may continue to require considerable attention; thus, it is imperative to explore the current happenings and pay attention to the future trajectory of heat stress effects on poultry production

Nigerian indigenous hens show more discomfort-related behavior with visual separation than physical separation from their chicks: An exploratory study

The Nigerian indigenous hens exhibit their full natural behavior repertoires, including maternal care. The strong maternal bond between the hen and her chicks is established prior to hatching. Maternal care of chickens is essential for both exotic and indigenous chickens. This study compared the behaviors of six hen-chick pairs in a physical (PHY) and visual (VIS) separation test for 10 min. All the six hen-chick pairs were subjected to PHY separation on the 8th day of post-hatch and a VIS separation on the 12th day of post-hatch. The PHY separation involved the use of a wire mesh to separate the hen from her chicks, while the VIS separation involved the use of a trampoline to separate the hen from her chicks. The hen's behavior was recorded during the 10-min separation period. Behaviors recorded included sitting, body shaking, pecking, movements toward the chicks, jumping, pacing, defecation, movements away from the chicks, and preening. We further grouped these nine behaviors into two categories: discomfort-related (pacing, movement toward chicks, body shaking, defecation, and jumping) and comfort-related (sitting, pecking, preening, and movement away from the chicks) behaviors. Before and after each separation, the hens were gently restrained, and a drop of blood was sampled from the wing vein to determine the blood glucose level. Their heart rate and eye temperature were also measured. A two-related samples test (Wilcoxon) was used to compare the behavior of the hens when subjected to the PHY and VIS separation. Eight out of the nine behaviors monitored did not differ between the separation types. However, the frequency of pacing by the hens was greater (z = −2.201, P = 0.028) in the VIS separation than in the PHY separation. Also, discomfort-related behavior was greater (t(5) = −2.717, P = 0.042) during the VIS separation than the PHY separation. Comfort-related behavior did not differ between the separation types. The change in eye temperature, heart rate, and blood glucose was similar in the two separation types. In conclusion, Nigerian indigenous hens displayed more discomfort-related behavior to the VIS separation from their chicks, but this was not associated with physiological responses indicative of stress.Peer Reviewe

Potentials of Exogenous Melatonin Administration on Growth and Performance of West African Dwarf bucks

The effect of exogenous melatonin (EM) on growth, physiological and haematological parameters of West African dwarf (WAD) bucks was evaluated in the experiment. Intact selected sixteen WAD bucks were distributed into 4 treatment groups of 0, 3, 6 and 9 mg EM. Bucks were orally dozed with EM 3 times per week for 16 weeks. Blood samples were collected at 0th week, 8th week and 16th week of experiment for evaluation of haematological parameters. Analysis of Variance was carried out and significant means were separated using SAS. Results showed bucks given 6 mg EM had higher average daily weight gain of 31.3 g compared with others. Feed and water intake were similar across treatments, but feed conversion ratio was significantly lower in bucks given 6 mg EM. Values recorded in the morning of data collection days showed pulse and respiratory rates to be significantly different, with bucks given 6 mg of EM having lowest values.  6 mg group was also different for packed cell volume (32.57%), haemoglobin (10.72g/dl), red blood cell (11.38 1012 /L), neutrophil (35.50%) and lymphocyte (64.30%). Therefore, dose of 6 mg/animal EM influences growth performance, physiological and haematological parameters of WAD bucks positively and is therefore recommended for WAD bucks for optimal performance

Growth, Mineral Deposition, and Physiological Responses of Broiler Chickens Offered Honey in Drinking Water during Hot-Dry Season

Growing broilers were offered either 0 (0H), 10 (10H), 20 mL (20H) honey, or 0.5 g vitamin C/litre water (AA) during hot-dry season. Honey had no significant (>0.05) effect on feed intake (FI), weight gain (WG), feed conversion ratio (FCR), water intake (WI), survival (SURV), dressed percentage (DRE), breast meat (BRE), gizzard (GIZ), drumstick (DRU), shank (SHA), thigh (THI), tibia volume (VOL), and magnesium (MAG). Effect of honey was significant (0.005). Higher dose of honey lowered PR and HR. Honey significantly (0.05) affected. 20H broilers had higher THY than 0H and 10H groups. In conclusion, honey did not affect growth but might improve broilers’ welfare when offered up to 20H during hot periods

Hepatoprotective Effects of Vernonia amygdalina (Astereaceae) Extract on CCl4-Induced Liver Injury in Broiler Chickens

The aim of this study was to evaluate the effect of Vernonia amygdalina leaf extract (VALE) on the carbon tetrachloride-induced hepatotoxicity (CCl4) in broiler chickens. A total of 360-day-old broilers were divided into 4 treatments of 90 birds each consisting of 6 replicates of 15 birds each. The treatments were birds offered 1 mL/kg BW saline (control group), 100 mg/kg BW VALE, 1 mL/kg BW CCl4 (CCl4-treated group), and 100 mg/kg BW VALE + 1 mL/kg BW CCl4 (VALE + CCl4 group). Blood samples were collected at 42 days of age and analyzed for the liver enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and selected biochemical parameters. The experiment was laid out in a completely randomized design. The results obtained showed that VALE had the potential to mitigate the adverse effects of CCl4 on protein and lipid metabolism as reflected in the low serum malondialdehyde (MDA) levels, which is a marker of lipid peroxidation. The aqueous extract of Vernonia amygdalina (VA) at a dose of 100 mg/kg body weight showed a moderate hepatoprotective effect by reducing serum AST levels (p < 0.05). The levels of serum AST, ALP, ALT, and GGT were significantly increased in CCl4-treated birds compared to the control group, reflecting carbon tetrachloride-induced liver damage. The VALE + CCl4 group showed a significantly higher amount of ALP compared to birds treated with carbon tetrachloride, suggesting a hepatoprotective effect. To conclude, Vernonia amygdalina aqueous extract can be used to confer protection against hepatotoxicity, which can induce severe hepatocellular damage in birds

Effect of different levels of honey on physiological, growth and carcass traits of broiler chickens during dry season

The objective of this trial was to investigate the effect of different levels of honey in drinking water on the responses of broiler chickens during dry season in hot humid tropics. Three hundred Oba Marshall broiler chicks were used for this study. The day-old chicks were randomly assigned to five treatment groups with each treatment having four replicates of 15 birds. The first 4 treatment groups were daily supplied drinking water without honey (0H), with 20 ml (20H), 40 ml (40H) and 60 ml (60H) of honey per liter of water. The fifth group received drinking water supplemented with 500 mg vitamin C per liter of water (C). Records on daily weight gain (WG) and feed intake (FI) were taken. Feed conversion ratio (FCR) was calculated as the ratio of gain to feed consumed. The supplementation of honey in the drinking water for broiler chickens in 60H during hot dry season in the hot humid tropics improved some stress indices, body weight gain and relative spleen weight.</p

The productivity and resilience of the indigenous chickens in the tropical environments: improvement and future perspectives

ABSTRACTThe poultry population in Africa is mostly composed of local or indigenous chickens appreciated for the unique taste and texture of their meat. However, with the ever-increasing population growth, the free-range or backyard poultry farming system is no longer adapted to supply people with protein requirements. Crossbreeding local hens with an improved rooster weakens the thermotolerance and disease resistance of the offspring in African areas. In this context, the available breeds need to be preserved. The improvement of their productivity should be actualized through the implementation of a sustainable production programme that is simple and less expensive for the farmer, taking into account: feeding, habitat and chicken care. Scientific research should invest more time on the identification and characterization of all available breeds or chicken ecotypes allowing us to know production performances and their nutritional needs. Feeding with locally available resources, vaccination and use of indigenous medicine requiring training of farmers are essential perspectives. This paper focused on the productivity and resilience of indigenous chicken ecotypes in various African tropical environments and some essential factors to improve the birds. For this, a critical analysis was made based on the available data on the birds from research databases

EFFECT OF VITAMIN E ON SPERM AND OXIDATIVE STRESS PARAMETERS OF WEST AFRICAN DWARF GOAT BUCKS

The aim of the present study was to determine the effect of supplementation of vitamin E on sperm and oxidative stress parameters in West African Dwarf goat bucks. The bucks were allocated to 4 treatments consisting of 0 mg, 15 mg, 30 mg and 45 mg of vitamin E. At the end of 30 days consecutive administration of vitamin E, semen and blood samples were collected and evaluated for sperm and oxidative stress parameters. The results showed that sperm motility, acrosome integrity, membrane integrity and live spermatozoa; seminal Malondialdehyde (MDA), arginase activity and leukocytes; and serum MDA and testosterone were similar in all the levels of inclusion and comparable to the control. However, higher arginase activities were observed in all the levels of vitamin E compared to the control while 15 mg of vitamin E had higher percentage of sperm abnormality compared to other treatments and the control. The findings indicated that the levels of vitamin E used did not have beneficial effect on the sperm and oxidative stress parameters. Further study of higher levels of vitamin E is therefore necessary to ascertain the appropriate level required for optimal improvement in these parameters

Antioxidant status, hematology, performance, organ and carcass evaluation of heat-stressed broiler chickens fed with dietary Bambusa vulgaris leaf meal

Objectives: The objective of this study was to evaluate the inclusion of bamboo leaf meal (BLM) in broiler chicken feed to alleviate heat stress. Materials and Methods: This investigation was conducted following institutional policies guiding the handling of animals as approved for scientific research. 150 heat-stressed Arbor Acres broiler chickens were divided randomly into five dietary treatments, T1–T5, of 30 per treatment and 10 per replicate, to determine the consequence of feeding BLM on health and performance. Birds in T1–T4 were fed 0%, 1%, 1.5%, and 2% BLM-included diets, respectively, while T5 had a 0.2% vitamin C-included diet. Results: Increasing dietary BLM positively impacted body weight gain, feed intake, feed conversion rate (FCR), and stress indices levels. Broiler chickens had better feed intake (267 gm), weight gain (1,504 gm), and FCR (3.64) in T4. Serum glutathione peroxidase and malondialdehyde levels were not statistically different with increasing dietary BLM, while corticosterone levels were lower for chickens fed with dietary BLM. The superoxide dismutase index levels did not follow a particular pattern as dietary BLM increased. The hematology, carcass, and organ quality were unaffected by dietary BLM inclusion. Conclusion: BLM inclusions up to 2% in the broiler diet ameliorate heat stress conditions and improve performance without imposing any detrimental impact on the birds. [Vet. Res. Notes 2023; 3(4.000): 29-35