Inhibition of corticosterone synthesis and its effect on acute phase proteins, heat shock protein 70, and interleukin-6 in broiler chickens subjected to feed restriction.

The aim of the current study was to elucidate whether inhibition of corticosterone (CORT) synthesis could modify stress response to feed deprivation and its possible interactions with feed restriction in the neonatal period in broiler chickens. Equal numbers of broiler chicks were subjected to either 60% feed restriction (60FR) or ad libitum (AL) on d 4, 5, and 6. On day 7, blood CORT, acute phase proteins (APP), interleukin-6 (IL-6) levels, and brain heat shock protein 70 (HSP70) expression were determined. On d 35, chickens in each early age feeding regimen were subjected to one of the following treatments: (i) ad libitum feeding (ALF), (ii) 24 h feed deprivation (SFR), or (iii) 24 h feed deprivation with intramuscular injection of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) at 100 mg/kg BW (SFR+DDT). The effect of SFR on CORT, APP, IL-6, and HSP 70 were determined on d 36. The results showed that subjecting chicks to 60FR significantly elevated CORT and brain HSP70 concentration compared to the AL group on d 7. The early feeding regimen had no significant effect on CORT, alpha-1 acid glycoprotein (AGP), ovotransferrin (OVT), ceruoplasmin (CP), IL-6, or brain HSP70 on d 36. The CORT, AGP, OVT, CP, IL-6, and brain HSP70 expression of SFR birds following 24 h of feed deprivation (d 36) were significantly higher than their ALF and SFR+DDT counterparts. Both ALF and SFR+DDT birds had similar values. Stress attributed to feed deprivation without concurrent increase in CORT had a negligible effect on serum levels of APP and IL-6 and brain HSP70 expression.

Effects of low-protein diets on acute phase proteins and heat shock protein 70 responses, and growth performance in broiler chickens under heat stress condition.

A study with a 4 × 2 factorial arrangement was conducted to investigate the effects of 4 dietary protein levels and 2 environmental conditions on acute phase proteins (APP), brain heat shock protein (HSP) 70 density, and growth performance of broiler chickens. Day-old broiler chicks (Cobb 500) were fed isocaloric diets but with various levels of crude protein (CP), namely, (1) 21.0 and 19.0% CP in starter and finisher diets, respectively (control), (2) 19.5 and 17.5% CP in starter and finisher diets, respectively (Diet A), (3) 18.0 and 16.0% CP in starter and finisher diets, respectively (Diet B), and (4) 16.5 and 14.5% CP in starter and finisher diets, respectively (Diet C). Equal numbers of birds from each diet were subjected to either 23±1°C throughout or 33±1°C for 6 h per d from 22 to 35 d of age. From d 1 to 21, feed intake (FI) and weight gain (WG) decreased linearly (P = 0.021 and P = 0.009, respectively), as CP level was reduced. During the heat treatment period (d 22 to 35), there were significant (P = 0.04) diet × heat treatment interactions for FCR. Diet had no effect on FCR among the unheated birds, but the ratio increased linearly (P = 0.007) as dietary CP level decreased. Irrespective of ambient temperature, there was a significant linear decrease in FI (P = 0.032) and WG (P < 0.001) as dietary CP level decreased. Low-CP diets improved the survivability of heat-stressed broilers when compared to those fed control diets. Low-CP diets linearly decreased (P < 0.01) APP (ovotransferrin and alpha-acid glycoprotein) responses. Both APP and HSP 70 reactions were elevated following heat treatment. In conclusion, feeding broilers with low-CP diets adversely affect the growth performance of broilers under heat stress condition. However, low-CP diets were beneficial in improving the survivability. Because APP are involved in the restoration of homeostasis, the adverse effect of low-CP diet on the synthesis of these proteins could be of concern.

Protective potential of Lactobacillus species in lead toxicity model in broiler chickens.

To alleviate adverse effects of heavy metal toxicity, diverse range of removing methods have been suggested, that is usage of algae, agricultural by-products and microorganisms. Here, we investigated lead (Pb) biosorption efficacy by two lactic acid bacteria species (LABs) in broiler chickens. In an in vitro study, Pb was added to culture medium of LABs (Lactobacillus pentosus ITA23 and Lactobacillus acidipiscis ITA44) in the form of lead acetate. Results showed that these LABs were able to absorb more than 90% of Pb from the culture medium. In follow-up in vivo study, LABs mixture was added to diet of broiler chickens contained lead acetate (200 mg/kg). Pb exposure significantly increased lipid peroxidation and decreased antioxidant activity in liver. The changes were recovered back to normal level upon LABs supplementation. Moreover, addition of LABs eliminated the liver tissue lesion and the suppressed performance in Pb-exposed chicks. Analysis of liver and serum samples indicated 48% and 28% reduction in Pb accumulation, respectively. In conclusion, results of this study showed that L. pentosus ITA23 and L. acidipiscis ITA44 effectively biosorb and expel dietary Pb from gastrointestinal tract of chickens.

Dietary supplementation of L-glutamine and L-glutamate in broiler chicks subjected to delayed placement.

This study was conducted to investigate the effect of dietary glutamine (Gln) + glutamic acid (Glu) supplementation on growth performance and physiological stress response in broiler chickens subjected to 24 h delay in placement. Equal number of day-old broiler chicks were assigned to either immediate placement or with 24 h delay in placement with no access to feed and water. Chicks from each placement group were fed either standard starter diet (control) or standard starter diet +1% AminoGut (AG; mixture of 10% Gln and 10% Glu) from 1 to 21 d. Blood and duodenal samples were collected at 21 d for analysis of serum levels of ceruloplasmin (CER), ovotransferin (OVT) and α-1 acid glycoprotein (AGP), duodenal heat shock protein (HSP) 70 expression, and villi length and crypt depth. Results showed that delayed placement for 24 h was detrimental to weight gain during the starter phase (1 to 21 d) but not thereafter. AG supplementation was not able to eliminate that reduction in weight gain and feed intake during the starter stage. However, the observed enhancement in villi length and crypt depth at d 21 resulted in improvement of FCR and weight gain during the finisher stage (22 to 42 d) and consequently the overall period (1 to 42 d). Broiler chickens supplemented with AG also showed lower mortality rate, and higher AGP, OVT, CER, and HSP 70 expression compared to their control counterparts. Based on AGP, OVT, CER, and HSP 70 expression, there is no indication that delayed placement was physiologically stressful to the broiler chickens at 21 d of age.

Higher inclusion rate of canola meal under high ambient temperature for broiler chickens.

Extruded canola meal (ECM) was included in diet of broiler chickens at 0, 10, 20, and 30% (wt/wt) from 1 to 35 days of age. A total of 240 day-old male chicks were assigned in groups of 5 to 48 battery cages in environmentally controlled chambers and diets were replicated with 12 cages/treatment. From d 29 to 35, birds from each dietary group were exposed to either thermoneutral (23 ± 1°C; unheated) or high (36 ± 1°C; heated) temperature conditions. High ambient temperature, irrespective of ECM inclusion, depressed the growth performance of birds. Inclusion of ECM increased feed conversion ratio (FCR) linearly in unheated birds during d 1 to 28 (P < 0.001) and d 29 to 35 (P = 0.001). However, no adverse effects of ECM inclusion were observed on the growth performance of heated birds. The absence of these detrimental effects could be associated with the lack of triiodothyronine (T3) elevation by ECM inclusion in heated birds. In conclusion, ECM can be fed, at least, up to 30%, without any adverse effect on growth performance of broiler chickens raised under chronic high ambient temperature.

Acute phase proteins response to feed deprivation in broiler chickens.

Feed deprivation in poultry farming imposes some degree of stress to the birds, and adversely affects their well -being. Serum levels of acute phase proteins (APP) are potential physiological indicators of stress attributed to feed deprivation. However, it has not been determined how long it takes for a measurable APP response to stressors to occur in avian species. An experiment was designed to delineate the APP and circulating levels of corticosterone responses in commercial broiler chickens to feed deprivation for 30 h. It was hypothesized that feed deprivation would elicit both APP and corticosterone (CORT) reactions within 30 h that is probably associated with stress of hunger. Twenty-one day old birds were subjected to one of 5 feed deprivation periods: 0 (ad libitum, AL), 6, 12, 18, 24, and 30 h. Upon completion of the deprivation period, blood samples were collected to determine serum CORT, ovotransferrin (OVT), α1-acid glycoprotein (AGP), and ceruloplasmin (CP) concentrations. Results showed that feed deprivation for 24 h or more caused a marked elevation in CORT (P=0.002 and P<0.0001, respectively) when compared to AL. However, increases in AGP (P=0.0005), CP (P=0.0002), and OVT (P=0.0003) were only noted following 30 h of feed deprivation. It is concluded that elicitation of AGP, CP, and OVT response may represent a more chronic stressful condition than CORT response in assessing the well-being of broiler chickens.

Individual non-essential amino acids fortification of a low-protein diet for broilers under the hot and humid tropical climate.

A study was conducted to investigate the effects of feeding low-protein diets fortified with individual non-essential amino acids (NEAA) on growth performance, serum metabolites (uric acid, UA; triglycerides, TG; total protein, TP; and albumin, Alb), organ weight, breast yield, and abdominal fat weight in broiler chicks raised under the hot and humid tropical climate. Eight isocaloric (3,017 kcal/kg) experimental diets were formulated and fed to male broiler chicks from d 1-21 as follows: 1) 22.2% crude protein (CP) (positive control; PC); 2) 16.2% CP + mixture essential amino acids (EAA) to meet or exceed the National Research Council (1994) recommendations (negative control; NC); 3) NC + glycine (Gly) to equal the total glycine + serine level in the PC; diets 4 through 7 were obtained by supplementing NC diet with individual glutamic acid, proline, alanine, or aspartic acid (Glu, Pro, Ala, or Asp, respectively); 8) NC + NEAA (Gly + Glu + Pro + Ala + Asp) to equal the total level of these NEAA in the PC. Fortifying NC diet with mixture NEAA resulted in a similar growth performance as PC. However, fortification of low-CP diet with individual NEAA failed to improve body weight (BW) (P < 0.0001), feed intake (FI) (P = 0.0001), and feed conversion ratio (FCR) (P = 0.0001). Serum uric acid (UA) was lower (P = 0.0356) in NC birds and NC diet supplemented with individual NEAA birds, whereas serum triglyceride (TG) (P = 0.007) and relative weight of abdominal fat (P = 0.001) were higher in these birds. In conclusion, no single NEAA fortification may compensate the depressed growth performance attributed to a low-CP diet. However, fortification with Gly may improve FCR. There is a possibility that broilers raised under the hot and humid climate require higher Gly fortification than the level used in this study.

The effect of different degrees of feed restriction on heat shock protein 70, acute phase proteins, and other blood parameters in female broiler breeders.

The aim of the current study was to determine the physiological response to feed restriction in female broiler breeders using a range of conventional and novel indicators. One hundred female breeders were subjected to one of five feeding regimens from d 28 to 42 as follows (i) ad libitum feeding (AL), (ii-v) 75, 60, 45, and 30% of ad libitum feed intake. Blood heterophil to lymphocyte ratio (HLR), and plasma circulating corticosterone (CORT), ghrelin (GHR), serotonin (5-HT), and dopamine (DA) and serum acute phase proteins (APP) concentrations together with brain heat shock protein (HSP) 70 level were measured. The results showed a significant effect of feed restriction on blood HLR and plasma CORT, GHR, 5-HT, DA, and brain HSP 70 levels. However, feed restriction had no effect on serum levels of APP of alpha-1 acid glycoprotein, ovotransferin, and ceruloplasmin. Serum levels of 5-HT and GHR varied curvilinearly with the feed restriction level. The relationship between brain HSP 70 and level of feed restriction was negligible. However, significant linear relationships between HLR, CORT, DA, and the level of feed restriction were noted. Thus, these 3 parameters appear to represent a straight forward relation with severity of feed restriction.

Acute phase proteins, interleukin 6, and heat shock protein 70 in broiler chickens administered with corticosterone.

An experiment was conducted to determine the effect of corticosterone (CORT) administration on serum ovotransferrin (OVT), α1-acid glycoprotein (AGP), ceruloplasmin (CPN), and IL-6 concentrations, and brain heat shock protein (HSP) 70 expression in broiler chickens. From 14 to 20 d of age, equal numbers of birds were subjected to either (i) daily intramuscular injection with CORT in ethanol:saline (1:1, vol/vol) at 6 mg/kg of BW, or (ii) daily intramuscular injection with 0.5 mL ethanol:saline (1:1, vol/vol; control). Blood samples were collected before CORT treatment (14 d old), 3 and 7 d after CORT injections, and 4 d after cessation of CORT administration for determination of serum levels of CORT, OVT, AGP, CPN, and IL-6. Brain samples (whole cerebrum) were collected to measure HSP 70 density. Although CORT administration significantly increased feed intake, weight gain was significantly depressed. Administration of CORT also increased CORT, OVT, CPN, AGP, IL-6, and HSP 70 expression. Four days following cessation of CORT administration, OVT declined to the basal level but not CPN and AGP. In conclusion, an elevation in CORT can induce an acute-phase response and HSP 70 expression. Thus, APP and HSP 70 may be of value as indicators of stress in poultry.

Response to dietary supplementation of L-glutamine and L-glutamate in broiler chickens reared at different stocking densities under hot, humid tropical conditions.

A study was conducted to determine whether supplementing AminoGut (a commercial dietary supplement containing a mixture of l-glutamine and l-glutamic acid) to broiler chickens stocked at 2 different densities affected performance, physiological stress responses, foot pad dermatitis incidence, and intestinal morphology and microflora. A randomized design in a factorial arrangement with 4 diets [basal diet, basal diet + 0.5% AminoGut from d 1 to 21, basal diet + 0.5% AminoGut from d 1 to 42, and basal diet + virginiamycin (0.02%) for d 1 to 42] and 2 stocking densities [0.100 m(2)/bird (23 birds/pen; LD) or 0.067 m(2)/bird (35 birds/pen; HD)]. Results showed that villi length and crypt depth were not changed by different dietary treatments. However, birds in the HD group had smaller villi (P = 0.03) compared with those of the LD group. Regardless of diet, HD consistently increased the serum concentrations of ceruloplasmin, α-1 acid glycoprotein, ovotransferin, and corticosterone (P = 0.0007), and elevated heterophil to lymphocyte ratio (0.0005). Neither AminoGut supplementation nor stocking density affected cecal microflora counts. In conclusion, under the conditions of this study, dietary supplementation of AminoGut, irrespective of stocking density, had no beneficial effect on growth performance, intestinal morphology, and physiological adaptive responses of broiler chickens raised under hot and humid tropical conditions. However, AminoGut supplementation from d 1 to 42 was beneficial in reducing mortality rate. Also, the increased serum concentrations of a wide range of acute phase proteins together with elevated corticosterone and heterophil to lymphocyte ratio suggested that high stocking density induced an acute phase response either indirectly as a result of increased incidence of inflammatory diseases such as foot pad dermatitis or possibly as a direct physiological response to the stress of high stocking density.

Schiff base metal derivatives enhance the expression of HSP70 and suppress BAX proteins in prevention of acute gastric lesion.

Schiff base complexes have appeared to be promising in the treatment of different diseases and disorders and have drawn a lot of attention to their biological activities. This study was conducted to evaluate the regulatory effect of Schiff base metal derivatives on the expression of heat shock proteins (HSP) 70 and BAX in protection against acute haemorrhagic gastric ulcer in rats. Rats were assigned to 6 groups of 6 rats: the normal control (Tween 20 5% v/v, 5 mL/kg), the positive control (Tween 20 5% v/v, 5 mL/kg), and four Schiff base derivative groups named Schiff_1, Schiff_2, Schiff_3, and Schiff_4 (25 mg/kg). After 1 h, all of the groups received ethanol 95% (5 mL/kg) but the normal control received Tween 20 (Tween 20 5% v/v, 5 mL/kg). The animals were euthanized after 60 min and the stomachs were dissected for histology (H&E), immunohistochemistry, and western blot analysis against HSP70 and BAX proteins. The results showed that the Schiff base metal derivatives enhanced the expression of HSP70 and suppressed the expression of BAX proteins during their gastroprotection against ethanol-induced gastric lesion in rats.

Dietary supplementation of Zingiber officinale and Zingiber zerumbet to heat-stressed broiler chickens and its effect on heat shock protein 70 expression, blood parameters and body temperature.

The present study was conducted to assess the effects of dietary supplementation of Zingiber officinale and Zingiber zerumbet and to heat-stressed broiler chickens on heat shock protein (HSP) 70 density, plasma corticosterone concentration (CORT), heterophil to lymphocyte ratio (HLR) and body temperature. Beginning from day 28, chicks were divided into five dietary groups: (i) basal diet (control), (ii) basal diet +1%Z. zerumbet powder (ZZ1%), (iii) basal diet +2%Z. zerumbet powder (ZZ2%), (iv) basal diet +1%Z. officinale powder (ZO1%) and (v) basal diet +2%Z. officinale powder (ZO2%). From day 35-42, heat stress was induced by exposing birds to 38±1°C and 80% RH for 2 h/day. Irrespective of diet, heat challenge elevated HSP70 expression, CORT and HLR on day 42. On day 42, following heat challenge, the ZZ1% birds showed lower body temperatures than those of control, ZO1% and ZO2%. Neither CORT nor HLR was significantly affected by diet. The ZO2% and ZZ2% diets enhanced HSP70 expression when compared to the control groups. We concluded that dietary supplementation of Z. officinale and Z. zerumbet powder may induce HSP70 reaction in broiler chickens exposed to heat stress.

Dietary methionine and n-6/n-3 polyunsaturated fatty acid ratio reduce adverse effects of infectious bursal disease in broilers.

This study was carried out to investigate the modulatory effects of dietary methionine and n-6/n-3 polyunsaturated fatty acids (PUFA) ratio on immune response and performance of infectious bursal disease (IBD)-challenged broiler chickens. In total, 350 one-day-old male broiler chicks were assigned to 1 of the 6 dietary treatment groups in a 3 × 2 factorial arrangement. There were 3 n-6/n-3 PUFA ratios (45, 5.5, and 1.5) and 2 levels of methionine (NRC recommendation and twice NRC recommendation). The results showed that birds fed with dietary n-6/n-3 PUFA ratio of 5.5 had higher BW, lower feed intake, and superior FCR than other groups. However, the highest antibody response was observed in birds with dietary n-6/n-3 PUFA ratio of 1.5. Lowering n-6/n-3 PUFA ratio reduced bursa lesion score equally in birds fed with n-6/n-3 PUFA ratio of 5.5 and 1.5. Supplementation of methionine by twice the recommendation also improved FCR and reduced feed intake and bursa lesion score. However, in this study, the optimum performance (as measured by BW, feed intake, and FCR) did not coincide with the optimum immune response (as measured by antibody titer). It seems that dietary n-3 PUFA modulates the broiler chicken performance and immune response in a dose-dependent but nonlinear manner. Therefore, it can be suggested that a balance of moderate level of dietary n-6/n-3 PUFA ratio (5.5) and methionine level (twice recommendation) might enhance immune response together with performance in IBD-challenged broiler chickens.

Epigenetic modification: possible approach to reduce Salmonella enterica serovar enteritidis susceptibility under stress conditions.

Stressors may influence chicken susceptibility to pathogens such as Salmonella enterica. Feed withdrawal stress can cause changes in normal intestinal epithelial structure and may lead to increased attachment and colonization of Salmonella. This study aimed to investigate modulatory effects of epigenetic modification by feed restriction on S. enterica serovar Enteritidis colonization in broiler chickens subjected to feed withdrawal stress. Chicks were divided into four groups: ad libitum feeding; ad libitum feeding with 24-h feed withdrawal on day 42; 60% feed restriction on days 4, 5, and 6; and 60% feed restriction on days 4, 5, and 6 with 24-h feed withdrawal on day 42. Attachment of S. Enteritidis to ileal tissue was determined using an ex vivo ileal loop assay, and heat shock protein 70 (Hsp70) expression was evaluated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and western blotting. Feed withdrawal stress increased S. Enteritidis attachment to ileal tissue. However, following feed withdrawal the epigenetically modified chickens had significantly lower attachment of S. Enteritidis than their control counterparts. A similar trend with a very positive correlation was observed for Hsp70 expression. It appears that epigenetic modification can enhance resistance to S. Enteritidis colonization later in life in chickens under stress conditions. The underlying mechanism could be associated with the lower Hsp70 expression in the epigenetically modified chickens.

The role of heat shock protein 70 in resistance to Salmonella enteritidis in broiler chickens subjected to neonatal feed restriction and thermal stress.

Environmental stressors may influence chicken performance and susceptibility to pathogens, such as Salmonella enteritidis. This study was conducted to determine the effects of heat shock protein (Hsp)70 expression on resistance to Salmonella enteritidis infection in broiler chickens subjected to heat exposure. Chicks were divided into 3 feeding regimens: ad libitum feeding (control); 60% feed restriction on d 4, 5, and 6 (FR60); and 60% feed restriction on d 4, 5, and 6 plus 1,500 mg/kg of quercetin (FR60Q). On d 35, all of the chickens were individually inoculated with 1 mL of Salmonella enteritidis (1.5 × 10(8) cfu/bird) and exposed to an ambient temperature of 37 ± 1°C and 70% RH for 3 h/d. The FR60 and FR60Q chickens had significantly lower Salmonella enteritidis colonization and lower Hsp70 expression than that of the control chickens following the heat exposure period. The least colonization was observed in the FR60Q group (1.38 log(10) cfu/g in the spleen and 1.96 log(10) cfu/g in the cecal content) and the highest was in the control group (2.1 log(10) cfu/g in the spleen and 4.42 log(10) cfu/g in the cecal content). It appears that neonatal feed restriction can enhance resistance to Salmonella enteritidis colonization in heat-stressed broiler chicks, and the underlying mechanism could be associated with the lower expression of Hsp70.

The relationship between adrenocortical function and Hsp70 expression in socially isolated Japanese quail.

Physiological responses to social isolation stress were compared in 56-day-old male Japanese quail. Birds were fed pretreated diets for 3 days as follows: (i) Basal diet (control); (ii) Basal diet+1500 mg/kg metyrapone (BM); (iii) Basal diet+30 mg/kg corticosterone (BCO); (iv) Basal diet+250 mg/kg ascorbic acid (BC); (v) Basal diet+250 mg/kg α-tocopherol (BE); (vi) Basal diet+250 mg/kg ascorbic acid and 250 mg/kg α-tocopherol (BCE). The birds were subsequently socially isolated in individual opaque brown paper box for 2 hours. Plasma corticosterone (CORT) concentration and heart and brain heat shock protein 70 (Hsp 70) expressions were determined before stress and immediately after stress. Two hours of isolation stress elevated CORT concentration significantly in the control and BE birds but not in the BC, BCE and BM birds. There was a significant reduction in CORT concentration after isolation stress in the BCO group. Isolation stress increased Hsp 70 expression in the brain and heart of control and BM birds. However, brain and heart Hsp 70 expressions were not significantly altered in the isolated BC, BCE and BE birds. Although, the CORT concentration of BM birds was not affected by isolation stress, Hsp70 expression in both brain and heart were significantly increased. Moreover, exogenous corticosterone supplementation did not result in elevation of Hsp 70 expression. It can be concluded that, although Hsp 70 induction had not been directly affected by CORT concentration, it may be modulated by the HPA axis function via activation of ACTH.

Neonatal feed restriction modulates circulating levels of corticosterone and expression of glucocorticoid receptor and heat shock protein 70 in aged Japanese quail exposed to acute heat stress.

This study aimed to determine the effect of neonatal feed restriction on plasma corticosterone concentration (CORT), hippocampal glucocorticoid receptor (GR) expression, and heat shock protein (Hsp) 70 expression in aged male Japanese quail subjected to acute heat stress. Equal numbers of chicks were subjected to either ad libitum feeding (AL) or 60% feed restriction on d 4, 5, and 6 (FR). At 21 (young) and 270 (aged) d of age, birds were exposed to 43 ± 1°C for 1 h. Blood and hippocampus samples were collected to determine CORT and Hsp 70 and GR expressions before heat stress and following 1 h of heat stress, 1 h of post-heat stress recovery, and 2 h of post-heat stress recovery. With the use of real-time PCR and enzyme immunoassay, we examined the hippocampal expression of GR and Hsp 70 and CORT. The GR expression of the young birds increased following heat stress and remained consistent throughout the period of recovery. Conversely, no significant changes were noted on GR expression of aged birds. Although both young and aged birds had similar CORT before and during heat stress, the latter exhibited greater values following 1 and 2 h of recovery. Within the young group, feeding regimens had no significant effect on Hsp 70 expression. However, neonatal feed restriction improved Hsp 70 expression in aged birds. Neonatal feed restriction, compared with the AL group, resulted in higher CORT on d 21 but the converse was noted on d 270. Neonatal feed restriction appears to set a robust reactive hypothalamo-pituitary-adrenal response allowing the development of adaptive, healthy, and resilient phenotypes in aged quail as measured by a higher hippocampal Hsp 70 expression along with lower CORT.

Physiological responses of 3 chicken breeds to acute heat stress.

Domestic animals have been modified by selecting individuals exhibiting desirable traits and culling the others. To investigate the alterations introduced by domestication and selective breeding in heat stress response, 2 experiments were conducted using Red Jungle Fowl (RJF), village fowl (VF), and commercial broilers (CB). In experiment 1, RJF, VF, and CB of a common chronological age (30 d old) were exposed to 36 ± 1°C for 3 h. In experiment 2, RJF, VF, and CB of common BW (930 ± 15 g) were subjected to similar procedures as in experiment 1. Heat treatment significantly increased body temperature, heterophil:lymphocyte ratio, and plasma corticosterone concentration in CB but not in VF and RJF. In both experiments and irrespective of stage of heat treatment, RJF showed lower heterophil:lymphocyte ratio, higher plasma corticosterone concentration, and higher heat shock protein 70 expression than VF and CB. It can be concluded that selective breeding for phenotypic traits in the domestication process has resulted in alterations in the physiology of CB and concomitantly the ability to withstand high ambient temperature compared with RJF and VF. In other words, domestication and selective breeding are leading to individuals that are more susceptible to stress rather than resistant. It is also apparent that genetic differences in body size and age per se may not determine breed or strain variations in response to heat stress.

Gastrointestinal tract morphological alteration by unpleasant physical treatment and modulating role of Lactobacillus in broilers.

1. An experiment was conducted to determine the effects of supposedly unpleasant physical treatment on broiler performance, small intestinal development and ameliorating role of probiotics. 2. The following treatments were applied from day one: (1) chicks exposed to normal human contact fed basal diet (control); (2) chicks were exposed to unpleasant physical treatment and fed basal diet (UPT-BD); and (3) chicks were exposed to unpleasant physical treatment and fed basal diet supplemented with Lactobacillus (UPT-BDL). Chicks were exposed to UPT from days 1 to 21. Different segments of gastrointestinal tract were sampled at 14, 28, 35 and 42 d of age. 3. Broilers of UPT-BD had lower feed consumption compared with control group at 7 d of age. Overall, UPT-BDL birds showed higher body weight gain (BWG) and better feed conversion ratio (FCR) over the course of the experiment. 4. Birds of UPT-BD had lower concentrations of lactic, propionic and butyric acids in the caecum as compared with other groups at 14 d of age. Acetic acid concentration was profoundly decreased in both UPT groups compared to the control. 5. Duodenal villus height of UPT-BD broilers showed a slight reduction compared to the control and UPT-BDL birds at 14 d of age. Afterwards until day 42, UPT-BDL birds showed the highest villus height among treatments in different parts of the small intestine. 6. The results suggested that, even though UPT did not have significant inhibitory effects on the development of the small intestine and broiler performance, it negatively affected bacterial metabolic end products in the caecum, which could be ameliorated by the addition of Lactobacillus.

Selected microbial groups and short-chain fatty acids profile in a simulated chicken cecum supplemented with two strains of Lactobacillus.

Among the bacterial fermentation end products in the chicken cecum, butyrate is of particular importance because of its nutritional properties for the epithelial cell and pathogen inhibitory effects in the gut. An in vitro experiment, operated with batch bioreactor, was conducted to quantify butyric-producing bacteria in a simulated broiler cecum supplemented with Lactobacillus salivarius ssp. salicinius JCM 1230 and Lactobacillus agilis JCM 1048 during 24 h of incubation. Selected bacterial species were determined by real-time PCR and short-chain fatty acids and lactate concentrations were monitored. The results showed that after 24 h of incubation, Lactobacillus supplementation significantly increased the number of lactobacilli, bifidobacteria and Faecalibacterium prausnitzii in medium containing cecal content and lactobacilli supplementation (Cc + L) compared with the control (Cc). Addition of lactobacilli did not alter Escherichia coli and Clostridium butyricum, whereas it significantly (P < 0.05) reduced Salmonella in treatment Cc + L compared with the Cc treatment. Propionate and butyrate formation were significantly (P < 0.05) increased in treatment Cc + L as compared with the Cc treatment. Lactate was only detected in treatment containing 2 Lactobacillus strains. After 24 h of incubation, acetate concentration significantly (P < 0.05) decreased in all treatments. It was suggested that lactate produced by Lactobacillus in the cecal content improved the growth of butyric producers such as F. prausnitzii, which significantly increased butyrate accumulation. Additionally, the results showed that butyrate and propionate inhibited Salmonella without influencing the E. coli profile.