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

Geospatial Investigation of Nigerian Honey and Detection of Anti-Enteric Biomarker

Geospatial mapping and antibacterial biomarkers were investigated in Nigerian honey used for therapeutic purposes in several communities affected with prevalent antibiotic-resistant enteric bacilli. Randomly collected enteric bacilli from faecal samples were biotyped and phenotypically assayed for antibiotic resistance and profiled for R plasmids. R plasmid molecular weight and multiantibiotic resistance index (MARI) relatedness were evaluated for resistance among phylogroups. Honey cidal activity, time kill kinetics, and bioactive markers were determined and analysed for geospatial distribution. More than 30% enteric biotypes were resistant to cotrimoxazole, ciprofloxacin, and tetracycline at MIC ≥16 μg/ml (P � 0.004). Two unrelated cluster complexes with diverse antibiotic resistance indices expressed high molecular weight plasmid (14.17 kbp) with 0.73 MARI to two classes of antibiotics. Among the resistant bacilli, only 24.3% (MIC90 500 mg/mL) and 8.1% (MBC90 1000 mg/mL) were susceptible to honey with evidence of 14.85% and 5.94% significant viable reduction at 2 × MIC to less than 2.50 Log10 CFU/mL (P < 0.05). Only alkaloids significantly regressed (P � 0.028) with susceptibility of resistant bacilli significantly correlate with bacteria inhibition (r � 0.534, P � 0.049) at optimal cutoff limit of 0.32 mg/ml. Antibacterial honey with significant alkaloid biomarkers was detected at 3°10′0–3°30′0E and 6°30′0–7°30′0N of Southwest Nigeria. Spatial mapping evidently indicated variation in honey physicochemical and bioactive compounds and identified geographical locations suitable for production of anti-enteric honey rich in alkaloids marker required for prevention and treatment of resistant enteric bacilli infections

Production of steroids by the ovary of the Japanese quail

This study examined the production of steroid hormones (progesterone, testosterone, oestradiol and oestrone) by ovarian follicles of the Japanese quail in relation to age and sexual maturity; the mechanisms of action of and control by pituitary hormones of steroid production, oviposition and ovulation during the ovulatory cycle of the laying quail were investigated. Female quail raised on a short photoperiod (8L:16D) remained sexually immature while those raised on a long photoperiod (16L:SD) became sexually mature. Plasma steroid hormone levels rose significantly just before the onset of lay, explaining the observed oviduct growth, yolk-formation, follicle growth, induction of first ovulation and onset of lay which were absent in photosuppressed birds. The sites and relative amounts of steroids produced in the hierarchy of follicles were investigated. The largest follicles produced predominantly progesterone while the medium-sized follicles produced oestrogen. An histochemical study performed on the yolk-filled follicles revealed that the granuloss and theca cells in the follicle contained 30-HSDH and 1 7P-HSDH enzyme respectively. These sites parallel the postulated sites of steroidogenesis in chicken follicles. The distribution of these enzymes in the cells of the hierarchy of follicles parallel the relative amounts and types of steroids produced in vitro. Ovine LH and HCG stimulated progesterone and testosterone production by the cells dispersed from the yolk-filled follicles using collagenase while oFSH stimulated oestrogen production. The responsiveness to LH and HCG increased with the size of the follicle while the responsiveness to oFSE decreased with size. The mechanisms of action of these hormones were shown to involve the adenylate cyclase system. Experiments were designed to study the underlying causes of the changes in steroid hormone levels during the ovulatory cycle of the quail. In vitro, steroid production by follicular cell::-harvested at 12, 6 and 2 hrs before the expected ovulation time showed that the capacity for steroid production during the cycle change both at basal level and in response to putative hormones. Generally steroid production increases in all follicles up to the time of the endogenous LH surge and decreased after it. The duration of this desensitization varied among follicles: the F2 resumed steroid production 2 bra before ovulation while the F1 did not. Injections of LH or LH RE 18 and 12 hrs before ovulation also caused differential increases in progesterone levels in the plasma. It is proposed that LH and PSH control steroidogenesis in the ovary of the quail and also through stimulation and desensitization control the transition of one follicle to another. Studies on the control of oviposition and ovulation by injections of LE, LH-RH and progesterone indicated that the exogenous LH surge causes ovulation and that LH release is controlled by hypothalamic LH-RH through progesterone feedback from the ovarian follicles. The existence of an ~ovarian rhythm~ in the production of an ovulation-inducing amount of progesterone through changes in the sensitivity of the follicular cells to gonadotrophin stimulation during the ovulatory cycle was demonstrated.</p

Gene expression, tissue distribution and potential physiological role of uncoupling protein in avian species

International audienc

Growth performance and physiological responses of broilers fed Stylosanthes hamata leaf meal in a hot tropical environment

Abstract Background Forage plants are considered an essential source of vitamins, protein and energy and could decrease the intake of the conventional diets by up to 10% if young quality forage plants are offered and about 7% of a broiler's daily protein needs and 3% of their daily calorie needs can be met by pasture. However, there is a paucity of data on the quantification of the herbage intake in broiler chickens. Objectives This trial was designed to determine the performance and physiological response of broilers fed diets containing Stylosanthes hamata leaf meal (SHLM) at 0%, 1%, 5%, 10%, 15% and 20% inclusion (weight for weight) in a basal diet of poultry. Methods Two hundred and forty‐day‐old Arbor Acres broiler chicks were used for this trial. They were allocated at random to each of the 6 dietary treatment groups with 4 replicates of 10 chickens each. The study lasted for 35 days, during which data were collected weekly. Results Results indicated no difference (p > 0.05) in body weight gain, feed consumption and feed conversion ratio of broiler chickens across all ages. Although the plasma triiodothyronine (T3) concentration of the birds was influenced at the sixth week of age, there was no consistency in the trend. At the eighth week of age, chickens on 15% SHLM had significantly (p  0.05) mean plasma creatinine values. Conclusions The study concluded that SHLM could be incorporated into broiler feed up to 20% without a deleterious impact on physiology and performance indices

Geospatial Investigation of Nigerian Honey and Detection of Anti-Enteric Biomarker

Geospatial mapping and antibacterial biomarkers were investigated in Nigerian honey used for therapeutic purposes in several communities affected with prevalent antibiotic-resistant enteric bacilli. Randomly collected enteric bacilli from faecal samples were biotyped and phenotypically assayed for antibiotic resistance and profiled for R plasmids. R plasmid molecular weight and multiantibiotic resistance index (MARI) relatedness were evaluated for resistance among phylogroups. Honey cidal activity, time kill kinetics, and bioactive markers were determined and analysed for geospatial distribution. More than 30% enteric biotypes were resistant to cotrimoxazole, ciprofloxacin, and tetracycline at MIC ≥16 μg/ml (P=0.004). Two unrelated cluster complexes with diverse antibiotic resistance indices expressed high molecular weight plasmid (14.17 kbp) with 0.73 MARI to two classes of antibiotics. Among the resistant bacilli, only 24.3% (MIC90 500 mg/mL) and 8.1% (MBC90 1000 mg/mL) were susceptible to honey with evidence of 14.85% and 5.94% significant viable reduction at 2 × MIC to less than 2.50 Log10 CFU/mL (P<0.05). Only alkaloids significantly regressed (P=0.028) with susceptibility of resistant bacilli significantly correlate with bacteria inhibition (r = 0.534, P=0.049) at optimal cutoff limit of 0.32 mg/ml. Antibacterial honey with significant alkaloid biomarkers was detected at 3°10′0–3°30′0E and 6°30′0–7°30′0N of Southwest Nigeria. Spatial mapping evidently indicated variation in honey physicochemical and bioactive compounds and identified geographical locations suitable for production of anti-enteric honey rich in alkaloids marker required for prevention and treatment of resistant enteric bacilli infections

Comparison of three lines of broilers differing in ascites susceptibility or growth rate. 2. Egg weight loss, gas pressures, embryonic heat production, and physiological hormone levels

Ascites is a metabolic disorder that accounts for over 25% of overall mortality in the broiler industry. This disorder is manifested between wk 5 and 6 posthatch, but there are previous indications that predisposition may be identified during embryonic development. In this current study, we determined embryonic physiological and metabolic parameters that maybe associated with ascites predisposition. For this purpose, we used broiler eggs from 3 lines that differed in ascites. sensitivity. These included an ascites-sensitive dam line (DAS), an ascites-resistant dam line (DAR), and an ascites-sensitive sire line (SASL). Eggs were incubated for 21 d under standard conditions. The following parameters were measured during incubation: egg weights at setting, egg weight losses at 18 d, embryo body weights and embryo heart weights throughout development, air cell partial gas pressures (pCO(2) and pO(2)) levels at d 18 and at internal pipping (IP); plasma triiodothyronine, thyroxine, and corticosterone levels at d 18, 111, and hatch; heat production from d 17 until hatch, hematocrit Values at hatch, and posthatch growth rate to 7 d along with hematocrit values. The data obtained revealed that,election for ascites sensitivity or rapid growth rate had no consistent influence on some of these parameters such that they could be wholly associated with ascites sensitivity for predictive purposes. Whereas differences in embryonic developmental patterns were apparent throughout embryonic development, these differences in physiological and metabolic parameters may be due partly to genetic differences unrelated to ascites sensitivity.status: publishe

Effect of a single in ovo injection of 2,3,7,8-tetra-chlorodibenzo-p-dioxin on protein expression in liver and ovary of the one-day-old chick analyzed by fluorescent two-dimensional difference gel electrophoresis and mass spectrometry

The polyhalogenated aromatic hydrocarbon 2,3,7,8-tetracliloroclibenzo-p-dioxin (TCDD) is an ubiquitously distributed environmental pollutant which can induce a broad spectrum of toxic responses in animals, including birds. in this study, we investigated the impact of 0 or 20 ng TCDD injections into the yolk of chicken eggs before start of development, on liver and ovarian protein expression in hatchlings using fluorescent two-dimensional difference gel electrophoresis (2-D-DIGE) under a pH range of 4-7, combined with MS. Despite considerable inter-individual variability, exposure to TCDD prior to the start of embryonic development resulted in significant changes in expression of a small set of proteins. Expression of fibrinogen gamma chain precursor in the liver and 60 kDa heat shock protein in the ovary were significantly higher as a result of the very early exposure to TCDD. NADH ubiquinone oxidoreductase (42 kDa subunit) and regucalcin expression was decreased by early TCDD treatment in the liver and ovary, respectively. These proteins could not be directly linked with drug metabolism per se but are involved in blood dotting, oxidative stress, electron transport, and calcium regulation. It remains to be elucidated how these changes in the hatchling might be linked to the observed long-term consequences during posthatch life of the chicken.status: publishe

Embryonic developmental plasticity of the chick: Increased CO2 during early stages of incubation changes the developmental trajectories during prenatal and postnatal growth

This study investigated the effect of non-ventilation of the incubator during the first 10 days of incubation on carbon dioxide (CO2) concentrations in the incubator and its effects on the embryonic and post-hatch development of the chicken (Gallus gallus). Two different incubation conditions were created, one incubator was kept at standard conditions, with adequate ventilation (V) and a second incubator was nonventilated (NV) during the first ten days of incubation, allowing the CO2 to rise. After the first 10 days, both incubations were continued under standard conditions. The experiment was repeated twice with different ages of the breeders (45 and 60 wks) which resulted in different CO2 levels at ED10 (1.5 and 1%). The CO2 concentration in the V incubators remained below 0.1% in these first 10 days. The eggs of the NV incubation showed higher pCO(2) levels in the air cell from ED10 until ED14 compared to the eggs of the V group. The NV embryos had significantly higher absolute and relative (to egg weight) body weights from ED10 until ED18, pointing to an accelerated embryonic growth. At internal pipping, the NV chick embryos had higher plasma corticosterone and T-3 levels and higher pCO(2) in the air cell. Chicks incubated under NV conditions hatched 10 h earlier in the first and 15 h earlier in the second experiment and the spread of hatch was narrower. During the post-hatch period, the NV chickens had a higher body weight compared to the V chickens. From these results, it is clear that higher levels of CO2 during the first ten days of incubation have persistent (epigenetic) effects during the incubation and early post-hatch period. (c) 2006 Elsevier Inc. All rights reserved.status: publishe