This study examines the effect of dietary supplementation with Lactobacillus acidophilus (LA) on the cholesterol levels, immune response, and productive performance of laying hens. A total of 216, 40-week-old, commercial Hy-Line brown chicken layers were randomly assigned into four treatment groups (18 birds × three replicates per group) and fed diet supplemented with 0 (control), 1 × 10⁹, 21 × 10⁹, and 31 × 10⁹ colony forming units (CFUs) of Lactobacillus acidophilus (LA) per kg of feed for six consecutive weeks. Results show that plasma triglycerides, low-density lipoprotein (LDL) and total cholesterols became lesser, while high-density lipoprotein (HDL) cholesterol became higher in LA-supplemented groups compared to the control. In addition, a significant reduction occurred in the liver and egg yolk cholesterol by LA supplementation. Moreover, the immunological parameters including antibody titer against sheep red blood cells (SRBCs), phytohemagglutinin (PHA)-wattle swelling test, and T- & B-lymphocyte proliferation were enhanced in laying hens supplemented with LA compared to the control hens. While the heterophil to lymphocyte (H/L) ratio decreased with LA supplementation, indicating low stress conditions in the treated hens. These positive effects for LA were further reflected on the productive performance of laying hens and improved egg production, egg weight, egg mass, and feed efficiency. Our findings indicate that LA probiotic could be recommended in laying hens’ diets for lowering egg yolk cholesterol with positive impacts on health and performance.

Propolis (PR) is a resin product of bee colonies that has rich bioactive antioxidant and bactericidal compounds. Endotoxin, a byproduct of bacterial growth, is reported to cause progressive induction of endogenous oxidative stress and has negative impacts on individual health and wellbeing. Hereby, we investigated the ability of PR to alleviate the oxidative stress and immunosuppression imposed by avian pathogenic Escherichia coli using laying hen as a based model. In this study, PR was dietary supplemented to hens for 4 weeks at a concentration of 0.1%. At the beginning of the 4th week of the experiment, hens from control and PR treatment were injected with E. coli (O157:H7; 10⁷ colonies/hen) or saline. The results showed significant (p < 0.05) negative impact of E. coli challenge on antioxidant status, immune response and productive performance. PR supplementation reduced (p < 0.05) inflammation markers levels (tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β)) and plasma corticosterone concentration. The antioxidant status was ameliorated with dietary PR supplementation to challenged hens, showing significant (p < 0.05) reduction in malondialdehyde (MDA) levels and increasing total antioxidant capacity (TAC) concentrations. Cell mediated, as well as, humeral immune response improved significantly (p < 0.05) with dietary PR verified by the enhancement of T- and B-lymphocyte proliferation and the positive respond to phytohemagglutinin (PHA). Leucocyte cells viability increased significantly and the apoptotic factor forkhead box O3 (Foxo3) was reduced with PR supplementation. The current study revealed that dietary PR supplementation can effectively be used as an organic feed additive to overcome the endogenous oxidative stress induced by endotoxins challenge.

The effects of heat stress on broiler performance and immunological response were explored using lighting-program manipulation as a potential tool. The study included 200 Cobb500 broiler chicks that were one day old at the time of recruitment. The birds were divided into four-compartment groups with similar environments (five cages per compartment, ten chicks per cage). Starting from the fourth day of age, birds of two compartments received a continuous lighting program (23L:1D a day; C.L. groups) while birds of the other two compartments received an intermittent lighting program (1L:3D 6 times per day; I.L. groups). Within each lighting program during 22–42 d of age, one group was subjected either to a thermoneutral temperature at 24 °C or heat stress at 35 °C. The results reveal that stress biomarkers, especially the plasma concentrations of corticosterone (CORT), tumor necrosis factor-alpha (TNF-α), and malondialdehyde (MDA) were relieved by 46%, 27%, and 51%, respectively, in the I.L. treatment groups compared to the C.L. program in broiler chicks subjected to heat stress. The liver function was also improved by 24% and 32% in AST and ALT levels, respectively, in the I.L. program compared to the C.L. program in stressed birds. Furthermore, the I.L. program positively influenced the immune response of the heat-stressed broilers. Eventually, the I.L. program increased the heat-stressed broilers’ body weight gain and feed conversion ratio. It can be concluded that applying the I.L. program to broiler chickens can effectively improve their physiological balance and growth performance under heat-stress conditions.

Citrullus colocynthis (CC) has been known as a natural medicinal plant with wide biological activities, including antioxidant, anti-inflammatory, and antilipidemic effects. The aim of this study was to investigate the effect of inclusion of the ethanolic extract of CC seeds (ECCs) into layer diets on the lipid profile, stress indicators, and physiological and productive performance of laying hens. A total of 216 forty-week-old commercial Hy-Line brown laying hens were randomly assigned into four equal groups (3 birds × 18 replicates per group) that received a basal diet supplemented with 0, 0.5, 1.0, and 2.0 g/kg of ECCs for 12 consecutive weeks. The first group served as a control. The results showed that ECCs at 1.0 and 2.0 g/kg significantly (p < 0.05) improved the productive and physiological performance compared to the other groups. In addition, stress indicators examined in the laying hens, including lipid peroxidation (malondialdehyde (MDA)), corticosterone hormone (CORT), tumor necrosis factor alpha (TNFα), and heat shock protein 70 (HSP70), were significantly alleviated after inclusion of ECCs into layer diets at the three levels compared to the control group. Furthermore, all ECC levels induced a significant reduction in plasma triglyceride (TG) and cholesterol (CH) levels in the plasma, liver, and egg yolk, whereas the highest levels were obtained with 2.0 g/kg of ECCs. Particularly important, a high linear correlation (R² = 0.60–0.79) was observed between increasing doses of ECCs and MDA, liver CH, and egg yolk CH concentrations and egg weight, feed intake, and feed conversion ratio; moreover, the correlation was extremely high (R² = 0.80–0.100) with the level of TG, CH, low-density lipoprotein CH, high-density lipoprotein CH, and CORT. These results indicated that dietary supplementation with 2.0 g/kg of ECCs could be considered a successful nutritional approach to producing healthier, lower-cholesterol eggs for consumers, in addition to enhancing the physiological and productive performance of laying hens by alleviating the stress of intensive commercial production.

The current research was conducted to study the effect of dietary supplemental of glycine (gly) levels 0.1 and 0.2 % on modulating productive performance in Mandarah (M) during laying period from 28 to 40 weeks (wks.) of age. The 1st treatment (T1) was fed the basic diet and served as the control treatment with no additional gly. The 2nd and 3rd treatments were fed the basic diet supplemented with 0.1 and 0.2 % gly/kg diet, respectively. Results indicated that hens fed (T2} and (T3) supplementation significantly improved feed conversion ratio for all intervals except from (28 to 30 wks. of age) compared to control. Egg number, egg weight and egg mass values were significantly increase in M hens fed diets containing T2 or T3 compared to control T1 during the whole period studied. Egg quality {shell (thickness and %), albumen %, yolk (% and index)} were significantly affected due to T2 and T3 supplementation to hens. Significant increases have been recorded in abdominal fat % and triglyceride (TG) values of hens in T2 and T3 compared to T1 (control) values at 40 (wks.) of age. Significant decreases have been recorded in litter traits (pH, moisture, nitrogen and ammonia %) of hens of T2 compared to control (T1) values at 40 wks. of age. The results of the current research indicated that gly supplementation during the laying period promoted the productive performance and had beneficial effects on quality of poultry litter.

This study was conducted to evaluate the effect of dietary supplemental of glycine (Gly) on modulating physiological and reproduction performance of Mandarah (M) local chickens. A total of 135 hens and 18 cocks, from 28 to 40 weeks of age were randomly assigned to 3 treatments, and each treatment (T) include 45 hens and 6 cocks divided in 3 replicates of 15 hens and 2 cocks each. The 1st group (T1) was fed the basal diet and served as a control group (without supplementation). The 2nd group and 3rd group were fed the basal diet supplemented with 0.1 and 0.2 %, Gly (1 and 2 gm/ kg diet), respectively.). The study showed that the cocks Gly treatments (0.1 and 0.2 %) were significantly (P<0.05) increased in the ejaculate volume, total sperm output, semen quality factor, total motile sperm, thyroxine (T4) and follicle-stimulating hormones (FSH) compared with control treatment. Chickens that received diet supplemented with 0.1 % Gly had significant higher sperm concentration, total antioxidant capacity (TAC), triiodothyronine (T3) than those of control T1. No significant differences among T2, T3 and control (T1) in sperm motility %, live sperm %, dead sperm %, abnormal sperm %, fertility, hatchability, catalase, glutathione enzyme and luteinizing hormone (LH). Conclusively, it could be recommended to supply layer diets with Gly for better physiologically performance during the laying period.