Marginal deficiencies of dietary arginine and methionine could suppress growth performance and immunological responses in broiler chickens

The present study was conducted to investigate the effects of different levels of dietary arginine (Arg) and methionine (Met) on performance, immune responses, and carcass characteristics of broiler chickens. A total of 540 day‐old Ross 308 broiler chicks were randomly assigned into the nine experimental diets, consisting five replicates of 12 birds each. Dietary treatments included three different levels (90%, 100%, and 110% of National Research Council [NRC] specifications) of either dietary Arg or Met, which were fed to the birds according to a 3 × 3 factorial arrangement of treatments during a 42 days feeding trial. Results showed that supplementation of Arg and Met into the deficient‐diets increased (p < .01) weight gains during all trial periods. Although average daily feed intake (ADFI) was not influenced by dietary treatments, increasing Arg up to 100% of NRC recommendations improved (p < .05) feed conversion ratio (FCR) throughout the trial period. Similarly, supplementation of deficient‐diets with Met improved FCR values. There was a significant (p < .01) Arg × Met interaction for ADFI during the starter period; increasing the dietary Arg level increased ADFI when the diets were deficient in Met, while had an opposite effect in diets containing higher dietary Met levels. On the other hand, dietary Met fortification improved (p = .067) FCR values to a greater extent in 110% Arg‐diets during the entire trial period. Although different levels of Arg and Met had no marked effects on carcass yield and abdominal fat percentage, supplemental Arg up to 100% of NRC values increased (p < .01) the relative weights of spleen and bursa of Fabricius. Furthermore, bursa weight was affected by Arg × Met interaction (p < .01), so that supplemental Arg level of 100% of NRC increased the relative bursa weight in birds that were fed diets containing 90% and 110% of Met. Serum uric acid level was decreased (p < .05) as a result of dietary Arg fortification up to 110% of NRC recommended values. Supplementation of deficient‐diets with Met decreased (p < .05) serum cholesterol level. Although Newcastle antibody titer was not affected by dietary Arg or Met levels, Arg fortification of deficient‐diets increased (p < .001) antibody responses against infectious bronchitis (IBV) and bursal (IBD) disease viruses. Similarly, Met supplementation of deficient‐diets increased IBD antibody titer. There were significant (p < .05) Arg × Met interactions for IBV and IBD titers; Met fortification of 110% Arg‐diets was more effective in increasing antibody titers. An increase in dietary Met level up to 100% of NRC values increased (p < .001) serum concentration of γ‐globulins. The present findings imply that supplemental Arg could affect feed efficiency and antibody responses when the diets were already fortified with a sufficient Met level.     

Exogenous protease supplementation of poultry by‐product meal‐based diets for broilers: Effects on growth,carcass characteristics and nutrient digestibility

An experiment was conducted to investigate the effects of three levels (0%, 3% and 6%) of poultry by‐product meal (PBM) with or without protease on broiler growth, carcass characteristics and nutrient digestibility from 1 to 35 days. Two hundred and forty birds (n = 240) were fed equi‐caloric and equi‐nitrogenous (ME 2850 kcal/kg; CP 20%) diets throughout the experiment. The enzyme supplementation increased feed intake (p < .01) and body weight gain (p < .01), but feed:gain remained unaffected (p > .05) from 1 to 21 days. Increasing level of PBM decreased feed intake (p < .05), but body weight gain was improved (p < .05) at 3% PBM level during 1 to 21 days. The feed:gain was improved (p < .05) in birds fed diets containing 3% PBM. The feed:gain was also improved in birds fed diets containing 3% PBM from 1 to 35 days. However, feed intake and body weight gain in birds fed diets containing PBM remained unaffected. An interaction (p < .01) on feed intake between enzyme and PBM was noticed during 1 to 21 days. However, no interaction was recorded for body weight gain and feed:gain. The per cent carcass yield improved (p < .01) in birds fed diets supplemented with enzyme. The per cent breast meat yield was depressed (p < .005) in birds fed diets containing PBM. Apparent metabolizable energy (p < .001), nitrogen retention (p < .01), apparent metabolizable energy corrected for nitrogen (p < .001), and apparent digestibility coefficient for nitrogen (p < .01) improved in birds fed diets containing enzyme; however, a reverse was noticed in those fed diets containing only PBM. In conclusion, inclusion of 3% PBM along with supplementation of exogenous protease improved performance and nutrient digestibility in broilers.     

Effects of dietary Lactobacillus acidophilus and Bacillus subtilis on laying performance,egg quality,blood biochemistry and immune response of organic laying hens

The objective of this study was to evaluate the effects of two different probiotic micro‐organisms on the performance, egg quality and blood parameters of organically reared hens. A total of 900 16‐week‐old Hy‐Line layer hybrids were randomly assigned to three groups of 300 birds each. The control (CTR) group was fed a corn–soya bean cake‐based diet; the L group was fed the same diet supplemented with 0.1% Lactobacillus acidophilus, while the B group was fed the same diet supplemented with 0.05% Bacillus subtilis. Data were recorded at the beginning (weeks 5 and 6: T1) and at the end (weeks 19 and 20: T2) of the experiment, and no differences in hen performance were recorded between dietary groups or sampling times. All of the investigated clinical chemistry parameters, except GGT, were affected by diet (p < 0.05), with the best results recorded for the probiotic‐treated groups. The immune‐response values showed higher blood bactericidal activity in the B and L groups at T2 (p < 0.05) and a lower lysozime concentration in the B group at T1. Higher antibody production against Newcastle disease virus was observed in the L group compared to the CTR (p = 0.013). No differences in oxidative status were recorded, and no effects of diet on egg quality were observed. Among the physical egg characteristics, only the Roche scale colour was affected by diet (p < 0.05): the egg yolk was paler in the L group. The age of the hen was the most relevant factor affecting physical egg characteristics. The chemical parameters of the egg were almost unaffected by supplementation with probiotics except for the lipid content, which decreased with the L diet (p < 0.05). Both probiotic inclusions had beneficial effects on hen metabolism and welfare, and L. acidophilus induced the best immune response.     

Effect of Royal Jelly on behavioural patterns,feather quality,egg quality and some haematological parameters in laying hens at the late stage of production

The aim was to elucidate the impact of Royal Jelly (RJ) on behavioural patterns, feather cover, egg quality and some blood haematological indices in laying hens (58–64 weeks of age). A total of 108 Tetra Brown laying hens were used in the current trial. The birds were divided into three equal groups (36 birds each). The pure RJ was prepared for immediate injection subcutaneously, as follows: the first treated group (RJ₁:100 mg/kg); the second treated group (RJ₂:200 mg/kg); the control group. The eating and drinking activities in the RJ₂ group were significantly (p = .009 and .015 respectively) higher than the control and RJ₁ groups. Furthermore, the aggressive pecks, feather pecks and threating behaviour in the RJ₂ group were significantly (p = .005, .001 and .039 respectively) lower than the control and RJ₁ groups. Both RJ‐treated groups had the best feather cover on the neck and abdomen regions (p = .010 and .001 respectively; Figure  1 ). Both RJ‐treated groups had a significantly higher eggshell ratio (p = .019) and shell thickness (p = .001) in comparison with the control group. The albumen height, Haugh units and yolk index in both RJ‐treated groups were significantly greater than those recorded in the control group (p = .026, .001 and .022 respectively). The erythrocyte and total leucocyte counts in the RJ₂ group were significantly higher than those reported in the control and RJ₁ groups (p = .029 and .013 respectively); however, the heterophil/lymphocyte (H/L) ratio and heterophil % in both RJ‐treated groups were significantly the lowest (p = .001 and .039). In conclusion, birds in the RJ₂ group had superior feather cover, welfare and behavioural indices, probably due to the impact of active flavonoids components of RJ on laying hen performance. Furthermore, the RJ‐treated groups had significantly improved egg quality parameters and some blood haematological indices.     

Effects of stocking density on growth performance,meat quality and tibia development of Pekin ducks

This study was performed to investigate the effects of stocking density on performance, meat quality and tibia development in Pekin ducks reared on a plastic wire floor. A total of 372 healthy, 21‐day‐old, male ducks with similar body weight (BW) were randomly allotted to stocking densities of five (low), eight (medium) and 11 (high) birds/m². Each group had six replicates. Results showed that compared with the low density group, medium and high stocking density caused a decrease in final BW at 42 days old, and in average daily gain, European performance index (p < .01) and meat pH at 45 min postmortem (p < .001), and an increase of meat drip loss (p < .01). High stocking density resulted in an increase of feed/gain ratio (p < .001), but a decrease of tibia calcium (p < .01) and phosphorus content (p < .05). Meat color, shear force values, tibia size (weight, length, and width) and breaking strength were not significantly influenced by stocking density. In conclusion, stocking density over eight birds/m² negatively affects growth performance, but meat quality and tibia development are not dramatically influenced. Based on this study, the stocking density of male Pekin ducks should be adjusted between five and eight birds/m².     

Effects of 25‐hydroxycholecalciferol with two D3 vitamin levels on production and immunity parameters in broiler chickens

This study was performed in Ross 308 chickens aged 1–21 days and aimed to evaluate whether the addition of 25‐hydroxycholecalciferol (25(OH)D₃) to broiler chicken diets affects their growth performance and immunity. A completely random 2 × 2 factorial arrangement was used with two levels of vitamin D₃ and the absence or presence of 25(OH)D₃, corresponding to four treatments based on sorghum + soya bean diets: (i) 200 IU of vitamin D₃/kg of feed (Diet 1) (NRC, 1994 ), (ii) Diet 1 + 69 μg of 25(OH)D₃/kg of feed (Diet 2), (iii) 5,000 IU of vitamin D₃/kg of feed (Diet 3) and (iv) Diet 3 + 69 μg of 25(OH)D₃/kg of feed (Diet 4). Each treatment was conducted with six replicates of 10 chickens each. Water and feed was supplied ad libitum. The results showed significantly increased growth and tibia ash (p < .05) in the birds fed 5,000, IU of vitamin D₃/kg + 25(OH)D₃. Additionally, the cellular immune response increased significantly (p < .05) in both treatments with added 25(OH)D_3. Based on the results obtained under the current test conditions, the addition of 25(OH)D₃ at a rate of 69 μg/kg to diets containing vitamin D₃ improved the cellular immune response and mineral deposition in the bones of broilers aged 1–21 days. Because these parameters are very important in modern poultry farming, these results indicate that supplementation with 25(OH)D₃ should improve broiler production.     

Deoxynivalenol induces oxidative stress,inflammatory response and apoptosis in bovine mammary epithelial cells

Deoxynivalenol (DON) is a toxic secondary metabolite produced by Fusarium graminearum. It is one of the most common feed contaminants that poses a serious threat to the health and performance of dairy cows. This study investigated the in vitro cytotoxicity of DON on bovine mammary epithelial cells (MAC‐T). DON at different concentrations (0.25, 0.3, 0.5, 0.8, 1 or 2 μg/ml) inhibited the growth of MAC‐T cells after 24 hr of exposure (p < .001). DON at 0.25 μg/ml increased lactate dehydrogenase (LDH) leakage (p < .05); decreased glutathione (GSH) levels (p < .001), total superoxide dismutase (T‐SOD) activity and total antioxidant capacity (T‐AOC; p < .01); and increased malondialdehyde (MDA) concentration (p < .01) in MAC‐T cells after 24 hr of exposure. We also observed that DON increased reactive oxygen species (ROS) levels in cells incubated for 9, 15 and 24 hr (p < .001). DON at 0.25 μg/ml triggered oxidative damage in MAC‐T cells. Furthermore, it induced an inflammatory response in the cells incubated for 9, 15 and 24 hr (p < .05) by increasing the mRNA expression levels of nuclear factor kappa B, myeloid differentiation factor 88 (MyD88), tumour necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), IL‐6, cyclooxygenase‐2 and IL‐8. We further examined the effect of DON on apoptosis. DON prevented normal proliferation of MAC‐T cells by blocked cell cycle progression in 24 hr (p < .001). In addition, the apoptosis rate measured using annexin V‐FITC significantly increased (p < .05) with increase in the mRNA expression level of Bax (p < .01) and increase in the Bax/Bcl‐2 ratio (p < .01) in cells incubated for 24 hr. In summary, DON exerts toxic effects in MAC‐T cells by causing oxidative stress, inducing an inflammatory response, affecting cell cycle and leading to apoptosis.     

Estradiol Effects on Secretagogue-Induced Prolactin Release: Disparity in Responses to Sulpiride,Exercise, Epinephrine,Prostaglandin-F2α, and Thyrotropin-Releasing Hormone

Three experiments were conducted (1) to assess the effects of estradiol pretreatment on the prolactin response to various secretagogues, and (2) to determine whether elevated plasma thyroxine concentrations altered the prolactin responses to those secretagogues. Geldings were available and were used because their prolactin and luteinizing hormone responses to estradiol and dopamine antagonists are known to be similar to those in seasonally anovulatory mares. In the first experiment, performed in summer, estradiol cypionate (ECP; 100 mg) treatment of geldings increased (P = .07) plasma prolactin concentrations before the onset of exercise, and repeated exercise bouts stimulated (P < .001) plasma prolactin concentrations after each bout; there was no interaction with estradiol pretreatment. Epinephrine injection (5 μg/kg of body weight) did not alter prolactin concentrations. Prostaglandin-F_2α administration (10 mg Lutalyse) stimulated (P < .001) prolactin concentrations, but there was no interaction with ECP pretreatment. Sulpiride administration (0.1 mg/kg of body weight) stimulated (P < .001) prolactin concentrations, and there was a greater (P = .038) response in ECP-treated geldings relative to controls. In the second experiment, performed in winter, ECP (50 mg) pretreatment of geldings before 21 days of daily thyrotropin-releasing hormone (TRH; 1.5 mg) injections did not alter prolactin secretion (P > .1); TRH stimulated prolactin secretion only after the very first injection. In the third experiment (performed in July), pretreatment of geldings with 50 mg of thyroxine in biodegradable particles (day 0) raised (P < .001) plasma thyroxine concentrations in plasma for the duration of the experiment, but had no effect on the prolactin responses to two exercise bouts on day 5, to an injection of prostaglandin-F_2α on day 9, or to an injection of sulpiride on day 13. The previously reported stimulation of plasma prolactin concentrations by estradiol pretreatment and subsequent sulpiride administration in mares, as evidenced herein in geldings, does not occur when prolactin is stimulated by exercise, prostaglandin-F_2α, or TRH. The practical impact of these data is that stimulation of prolactin concentrations after ECP treatment in winter, in an effort to stimulate ovarian activity in seasonally anovulatory mares, is likely limited to dopamine antagonists. Results of the third experiment indicate that TRH is not likely the mediator in the prolactin response to exercise or prostaglandin-F_2α injection.     

Production performance,immune response and blood biochemical parameters in broiler chickens fed diet incorporated with prebiotics

This experiment was conducted to identify the suitable replacer of broiler feed antibiotics with prebiotics (mannan oligosaccharides‐MOS or fructooligosaccharide‐FOS). Two hundred and forty (240)‐day‐old chicks were randomly divided into 30 groups (6 treatments x 5 replicates/treatment x 8 chicks/replicate). Six experimental diets T₁, T₂, T₃, T₄, T₅ and T₆ were formulated to contain an additional 0, antibiotic, that is, bacitracin methylene di‐salicylate (BMD) @20 mg/kg, MOS (0.1% and 0.2%) and FOS (0.1% and 0.2%) respectively. Body weight gain was significantly (p < 0.05) increased in MOS‐0.2% supplemented group at 0–21 d and 0–42 d of broiler chicken. Humoral and in vivo cell‐mediated immune response were significantly improved (p < 0.05) in BMD, MOS @0.1% or 0.2% treated group. Significant (p < 0.05) increase was recorded in total protein (except 21 d), albumin and aspartate amino transferase (AST) and decrease (p < 0.05) in alanine amino transferase (except 42 d), cholesterol and uric acid concentration. The weight of breast, thigh, back, drumstick bursa of Fabricius and thymus were higher (p < 0.05) in the birds given the MOS @0.2% (T₄). It is concluded that MOS @0.2% may be suitable replacer of antibiotic growth promoter, and it has a beneficial effect on production performance, immune responses, blood biochemical parameters and cut up parts in broiler chickens.     

Deoxynivalenol in chicken feed alters the vaccinal immune response and clinical biochemical serum parameters but not the intestinal and carcass characteristics

This study was conducted to investigate the impacts of deoxynivalenol (DON) feeding either alone or in combination with a microbial feed additive (MFA) on the immune response to a viral vaccine and serum clinical chemical parameters. Forty 1‐day‐old boiler chicks were weighed and randomly divided into four groups, 10 birds in each group: (i) control group fed with basal diet; (ii) DON group fed with basal diet artificially contaminated with 10 mg DON/kg feed; (iii) DON + MFA group fed with basal diet contaminated with 10 mg DON/kg feed and supplemented with 2.5 kg of MFA/ton feed; and (iv) MFA group fed with basal diet supplemented with 2.5 kg of MFA/ton feed. At 35 days of age, birds were slaughtered and blood was collected for investigating the antibody titre against infectious bronchitis virus (IBV) and clinical chemical parameters. The results showed that DON reduced (p = 0.032) the titre against IBV, decreased (p = 0.005) the level of alanine transaminase (ALT) (4.2 ± 0.5 U/l) compared with control birds (6.4 ± 0.5 U/l), increased (p = 0.002) the serum cholesterol concentration (144 ± 6 mg/dl) compared with their control counterparts (123 ± 5 mg/dl) and increased (p = 0.074) the amount of circulating triglycerides (62.25 ± 7.50 mg/dl) compared with controls (39.55 ± 4.74). These results indicate that dietary DON altered the humoral immune response to viral vaccine and affected the serum clinical biochemistry. However, DON in combination with MFA did not affect serum IBV titre. Taken together, DON in the feed of broilers produced an impairment of the success of IBV vaccine and affected the health of birds.     

Effect of dose and source of supplemental zinc on immune response and oxidative enzymes in lambs

An experiment of 150 days was conducted on 42 male Nellore lambs (28.3 ± 0.64 kg) to determine the effect of zinc (Zn) supplementation (0,15, 30 and 45 ppm) in diet from inorganic (ZnSO₄) and organic (Zn proteinate) sources on immune response and antioxidant enzyme activities by allotting them randomly to 7 groups in completely randomized design. The basal diet (BD) contained 29.28 ppm Zn. The humoral immune response assessed at 75 d against B. abortus was higher (P<0.01) with 15 or 30 ppm Zn supplementation from organic source. The dose and source had no effect on titres against chicken RBC antigen. The cell mediated immune response assessed as delayed type hypersensitivity (DTH) response against phytohaemagglutinin-P and in vitro lymphocyte proliferative response against concanavalin A at 150 d was higher (P<0.05) at 15 ppm Zn supplementation compared to BD fed lambs. Supplementation of 45 ppm Zn had no positive effect on immune response. The DTH response and antibody titres against B.abortus were higher (P< 0.05) on Zn proteinate compared to ZnSO₄ at 15 ppm Zn supplementation. The lipid peroxidase activity was lower (P < 0.01), while the RBC superoxide dismutase and catalase activities were higher (P < 0.01) in lambs at 15 ppm Zn supplementation compared to BD diet fed lambs, assessed at 75 d of feeding. Serum globulin concentration and alkaline phosphatase (ALP) activity (75 d of experiment) was higher in Zn supplemented lambs. The ALP activity increased (P < 0.01) with increase in Zn supplementation and being higher when supplementation was from Zn proteinate compared to ZnSO₄. The study indicated that 15 ppm zinc supplementation was required for obtaining higher immune response in lambs when fed a basal diet containing 29.28 ppm Zn and supplementation as Zn proteinate had higher antioxidant enzyme activities and immune response compared to ZnSO₄.     

Effect of vitamins,protein level and probiotics on immune response of moulted male broiler breeders

This study was planned to investigate the comparative effect of vitamins C (L‐ascorbic acid), E (DL‐α‐tocopherol acetate), probiotics, lower than normal protein level (14%) and combination of these treatments on immune response of male broiler breeders after zinc‐induced moulting. One hundred and eighty birds at the age of 65 weeks were induced to moult by mixing zinc oxide (ZnO) in feed at the rate 3000 IU/kg of feed. Upon completion of moulting, birds were divided into six groups (five replicates per group) in a completely randomized design and were fed vitamin C (500 IU/kg), vitamin E (100 IU/kg), lower protein level, probiotics (50 mg/l), and a combination of these components, while one group was kept as control. After completion of moulting phase (5 weeks), the treatment effects were tested as in vitro macrophages engulfment percentage, nitric oxide (NO) production, serum antibody titres against Newcastle disease (ND) and infectious bronchitis (IB). The results showed that in vitro macrophage engulfment percentage in unopsonized conditions was significantly higher in vitamin E‐supplemented group. In addition, in opsonized condition, the macrophage engulfment percentage was significantly higher in both vitamin E‐ and C‐supplemented groups. The NO (opsonized and unopsonized) production and antibody titre against ND and IB were significantly higher in vitamin E‐supplemented group. It was concluded that vitamin E is a better option for enhanced immune response in broiler breeders after zinc‐induced moulting.     

Effect of dietary manipulation and vaccination of turkey breeder hens on immunoglobulin levels of yolk,yolk sac and neonate poults

Two hundred turkey breeder hens and 24 viable toms of 30–35 weeks age of small white variety were distributed into two treatment groups having four replicates of 25 hens and three toms in each treatment. First four replicates were offered a turkey breeder diet (Diet A) (Nutrient requirements of poultry, 1994, National Academic Press, Washington, DC) and the rest four replicates were maintained on a higher plane of nutrition (Diet B) for 8‐week duration. After 6 weeks of experimental feeding, two replicates from each treatment groups were vaccinated with ND (R₂B) vaccine. Yolk sac of embryo from birds fed Diet B had a significantly higher (p < .05) IgG, IgM level and HI titre (log 2) than those fed Diet A. HI titre values of embryonic yolk sac from the vaccinated birds fed Diet B were significantly higher (p < .05) than that of the control groups. In addition, HI titre values were significantly higher (p < .05) in the day‐old poults of the birds fed Diet B than that of those fed Diet A. There was significantly (p < .01) positive correlation between serum IgG and IgM of the breeder birds and day‐old chicks. Similarly, there was significantly (p < .05) positive correlation between yolk IgG and IgM after 1‐month experimental feeding and yolk sac IgG and IgM. Positive correlation (p < .05) also existed between yolk sac IgM and day‐old chick serum IgM. Furthermore, the HI titres of breeder birds' serum at 14 days post‐vaccination were positively correlated with their egg yolk after 10 and 15 days post‐vaccination, yolk sac and day‐old chicks. Thus, the study envisaged that a higher immunity in neonate poults from turkey breeders maintained on a higher plane of nutrition may be elicited as there was maternal transfer of antibodies from the serum of breeder birds to their offsprings through their yolk sac.     

Effect of diets containing earthworm powder and vermihumus on egg production,hatchability, blood parameters and immunity of Japanese breeder quails

The present study is aimed to evaluate the effects of different levels of earthworm (EW) powder and vermihumus (VH) on the growth performance, humoral immunity response, plasma constituents and reproductive performance of Japanese breeder quails. A total of 336 birds were assigned to seven treatments in a completely randomized design from day 30 to 90 of age. The dietary treatments were carried out, one without any addition of EW and VH, the second had a standard rate of VH at 0.8%, while a range of EW additions was supplied from 0%, 0.5%, 1%, 1.5%, 2% and 2.5%. The effects of treatments on body weight and mortality were not significant (p > .05). The highest feed intake was observed in birds fed the diets supplemented with 1% and 1.5% EW (p < .05). The highest titre of antibodies against influenza virus and sheep red blood cells belonged to the EW and VH treatments (p < .05). The antibody titre against Newcastle disease virus vaccine was not affected by the treatments. In general, the birds receiving EW and VH had the highest egg weight, egg production and egg mass weight (p < .05). Nonetheless, various levels of EW powder negatively affected hatchability and increased mortality and leg disorders (p < .05). The results showed that the levels of dietary 1% and 1.5% of EW powder gave the best growth and reproductive performance to birds respectively.     

Effects of milk thistle meal on performance,ileal bacterial enumeration,jejunal morphology and blood lipid peroxidation in laying hens fed diets with different levels of metabolizable energy

This study was conducted to evaluate the effects of different levels of milk thistle meal on performance, blood biochemical indices, ileal bacterial counts and intestinal histology in laying hens fed diets containing different levels of metabolizable energy. A total number of 200 Leghorn laying hens (Hy‐Line W‐36) were randomly assigned to eight experimental treatments with five cage replicates of five birds each. Dietary treatments consisted of four levels of milk thistle meal (0%, 15%, 30% and 60%) and two levels of AME_n (11.09 and 12.34 MJ/kg) fed over a period of 80 days. In vitro studies revealed that the total phenolic component of milk thistle meal was 470.64 mg gallic acid equivalent/g of the sample, and its antioxidant activity for inhibiting the 2‐2‐diphenyl‐1‐picrichydrazyl free radical and reducing ferric ions was about 21% higher than that of butylated hydroxyltoluene (p < .05). Diets containing high level of AME_n led to improved egg production (p < .05), egg weight (p < .05), egg mass (p < .01) and feed conversion ratio (p < .01). In addition, offering diets containing high energy significantly enhanced (p < .01) serum triglyceride and malondialdehyde (MDA) concentrations as well as jejunal villus height. Dietary supplementation of 3% milk thistle meal resulted in the best feed conversion ratio (p < .05), reduction of ileal Escherichia coli enumeration (p < .01) and an enhancement in the villus height‐to‐crypt depth ratio (p < .05). Furthermore, feeding incremental levels of this meal led to remarkable decrease in serum cholesterol, triglyceride and MDA (p < .01) concentrations while significant increase in blood high‐density lipoprotein content and goblet cell numbers (p < .05). The present findings indicate that milk thistle meal with high antioxidant and antibacterial properties in laying hen diets may improve health indices and productive performance.     

The impact of cross‐breeding Egyptian and Italian buffalo on reproductive and productive performance under a subtropical environment

The aim of this study was to investigate the reproductive and productive performance of pure Egyptian (PE) buffaloes and their crosses with Italian buffaloes. In this study, 2969 dairy buffaloes were used (1599 PE; 615 F₁ crosses, 50% PE and 50% Italian buffaloes; and 755 backcross [BC], 75% PE and 25% Italian buffaloes). When compared to PE, the BC and F₁ had a significantly lower incidence of calving difficulty (odds ratio [OR] = 0.18, p < .0001 and .34, p < .0001, respectively) in conjunction with a lesser incidence of stillbirth (OR = 0.06, p < .0001 and 0.43, p < .0001, respectively). Backcross buffaloes were also noted to have a lower rate of not conceived after first insemination (OR = 0.74, p < .0001) in comparison with PE. The cross F₁ buffaloes were superior in terms of productive traits, whereas PE buffaloes were best in most of the reproductive traits (days of non‐pregnant p = .001, service per conception p < .0001 and calf weight p = .01). Although the study results appeared to indicate towards a contrary association between milk production and reproductive traits, BC was similar to F₁ in terms of production and similar to PE in terms of reproductive traits. Thus, the farmers should be encouraged to breed BC animals in their herds for enhancing milk yield to meet with the market demands.     

Nigella sativa (black cumin seed) as a biological detoxifier in diet contaminated with aflatoxin B1

Aflatoxin B₁ (AFB₁) is a common feed contaminant that adversely affects bird performance and product quality. A total of 600 7‐day‐old quail chicks were randomly allotted to eight experimental groups in a completely randomized design with five replicate pens and 15 quails per pen. Experimental treatments including two levels of AFB₁ (0 and 2.5 mg/kg) and 4 levels of Nigella sativa (NS) (0, 0.5, 1.0 and 1.5% of diet) were offered from 7 to 35 days of age to quail chicks. Although feeding of AFB₁ impaired gain (G) and feed conversion ratio, dietary NS increased G (p < 0.05). Relative weight of bursa of Fabricius increased with incremental levels of NS (p < 0.05). AFB₁ decreased the size of heart, but incremental levels of NS increased the relative weight of heart (p < 0.05). The liver hypertrophy was observed in birds receiving AFB₁ (p < 0.05). The birds in AFB₁ group had smaller testes than other groups (p < 0.05). Hematocrit value in birds fed AFB₁ was lower than that in other groups (p < 0.05) and incremental levels of NS increased blood hematocrit (p < 0.05). Amount of malondialdehyde (MDA) in meat samples of the birds fed AFB₁ was higher than those did not receive toxin but incremental levels of NS decreased the MDA concentration in affected birds (p < 0.05). AFB₁ suppressed the humoral immunity of the birds while NS augmented the antibody titres against sheep red blood cell and Newcastle disease virus antigens (p < 0.05). AFB₁ decreased lactic acid bacteria (LAB) and spore‐forming bacteria (SFB) but increased Escherichia coli (E. coli; p < 0.05). However, NS increased LAB and SFB but decreased the E. coli populations (p < 0.05). This study revealed that NS as a biological detoxifier could relatively attenuate the negative effects of AFB₁ in quails.     

The production of short chain fatty acid and colonic development in weaning piglets

Weaning process widely affects the small intestinal structure and function in piglets, while the responses of large intestine to weaning stress are still obscure. The purpose of this study was to determine the developmental changes (i.e., short chain fatty acids (SCFAs) concentrations, growth parameters, crypt‐related indices and antioxidant capacity) in colon of piglet during weaning. Forty piglets were weaned at day 21 and euthanized to collect colonic tissues and digesta samples on day 0, 1, 3, 7 and 14 post‐weaning (n = 8). Piglet growth performance was improved (p < .001) on day 7 and 14 post‐weaning. The concentrations of acetate, propionate, butyrate, valerate, isobutyrate, isovalerate and total SCFAs were higher (p < .001) during the late post‐weaning period. The mRNA abundances of SCFAs transporters were greater (p < .001) on day 7 and 14. The absolute and relative weights, absolute length and perimeter of colon were greater (p < .001) on day 7 and 14. Similarly, post‐weaning increases (p < .001) in colonic crypt depth and Ki67 positive cells numbers per crypt were observed during the same period. Colonic crypt fission indices decreased (p < .01), while total crypt numbers increased (p < .001) on day 14 after weaning. Moreover, total SCFAs concentration was significantly associated with colonic growth parameters and Ki67 cells/crypt (p < .001). In addition, catalase content was decreased on day 3, 7, and 14, whereas, the concentrations of total superoxide dismutase (T‐SOD) and manganese‐containing superoxide dismutase (MnSOD) were higher (p < .05) on day 1 and 3 post‐weaning. These results showed that weaning process has a significant effect on colonic growth and development, which might be associated with the change of SCFAs concentrations in colon.     

Lactobacillus rhamnosus GG promotes M1 polarization in murine bone marrow‐derived macrophages by activating TLR2/MyD88/MAPK signaling pathway

Lactobacillus rhamnosus GG (LGG) is increasingly applied in functional food products and acts as a probiotic model in nutritious and clinical studies. Increasing evidences have revealed the immune modulation of LGG on macrophages. The aim of this study is to investigate the effect of LGG on macrophage polarization of murine bone marrow‐derived macrophages (BMDMs). BMDMs were treated with 10⁸ colony‐forming units (CFU)/ml LGG for 1.5, 3, and 6 hr. Results showed that LGG obviously upregulated the mRNA expression of M1‐associated cytokines (p < .05), including interleukin‐1 beta (IL‐1β), IL‐6, tumor necrosis factor‐alpha (TNF‐α), and inducible nitric oxide synthase (iNOS), whereas had no effect on the expression of M2‐associated markers (p > .05), including arginase 1 (Arg1), mannose receptor, and chitinase‐like protein 3 (YM1). Furthermore, LGG markedly increased the expression of pro‐inflammatory cytokines (IL‐12p40, cyclooxygenase‐2 [COX‐2], and interferon‐γ [IFN‐γ]) (p < .05) and anti‐inflammatory cytokines (IL‐10, IL‐4, and transforming growth factor‐β [TGF‐β]) (p < .05). In addition, we also found that TLR2/MyD88/MAPK signaling pathway was required for LGG‐induced M1 macrophage polarization and M1‐related cytokines expression. Together, these findings demonstrate that probiotic LGG facilitates M1 polarization of BMDMs, suggesting that LGG may have an immunotherapeutic potential in regulating the host defense against pathogen invasion.     

Evaluation of the effects of sweet potato (Ipomoea batatas (L.) Lam) in broiler diets

Cereal grains such as maize and wheat are used extensively in feed formulations for poultry as the primary source of carbohydrates. High cost of these grains in many developing countries necessitates the evaluation of other ingredients that are grown locally. Sweet potato is one such crop. The study was conducted as a proof of concept experiment to test the hypothesis that in the presence and absence of enzyme, sweet potato roots when included in diets of broiler chickens may affect the total metabolisable energy content of the diets which may exert certain influences on dry matter digestibility of these diets as well as impacting on production and certain gut parameters. A total of 120 chicks were raised on a commercial starter feed from day 0 to 19. On day 22, the birds were individually weighed and allocated to 96 single bird metabolism cages to conduct a 7‐day classical apparent metabolisable energy (AME) assay. The test diets contained 0% and 25% sweet potato flour (SPF) with and without enzyme supplementation (Rovabio Excel AP T‐flex) and replicated 24 times. AME of the control diet with and without enzyme was 14.05 and 13.91 MJ/kg whilst the AME of the SPF diets with and without enzymes were 13.45 and 13.43 MJ/kg respectively. AME of SPF was 12.08 MJ/kg. Birds fed the SPF had significantly reduced end weights (p = .002) and weight gains (p < .001) leading to significantly higher intake (p = .004) and FCRs (p < .001) in birds. These effects in growth parameters highlight the need to balance dietary protein and total amino acids when using SPF in broiler diets and may not be a negative effect of SPF per say as AME and dry matter digestibility of SPF diets were comparable to the control diet. The level of sucrase activity in the jejunum was significantly (p < .001) lower due to enzyme inclusion. Use of SPF in the current study did not negatively influence the activities of the brush border enzymes maltase and sucrase, gut morphology in the jejunum of broilers or the load of Enterobacteriaceae in the caecal of birds. This finding is promising in that the gut parameters associated with digestive capacity and gut health were not compromised with feeding of SPF to broilers.