Effects of zinc oxide nanoparticles on the egg quality,immune response,zinc retention,and blood parameters of laying hens in the late phase of production

The objective of this study was to evaluate the effects of dietary supplementation with zinc oxide nanoparticles (ZnO‐NPs) on the performance, egg quality, Zn retention, immunity responses, superoxide dismutase activity (SOD), egg malondialdehyde (MDA) content, and serum parameters in laying hens in the late phase of production. A total of 288 laying hens at 64 weeks of age were randomly assigned to 4 treatments with 6 replicates, and 12 birds within each group. Experimental diets included a corn‐soybean meal‐based diet (without Zn supplementation) and a basal diet supplemented with 80 mg/kg of Zn‐oxide, ZnO‐NPs, and Zn‐methionine. The results indicated that egg production and egg mass were significantly higher in the Zn‐methionine and ZnO‐NPs groups (p < .05). Also, eggshell thickness and shell strength increased in the ZnO‐NPs group as compared with the other groups (p < .05). Moreover, Zn supplementation decreased egg loss (p < .05). There were significant differences among treatments in Zn deposition in tibiotarsus, liver, pancreas, eggs, and excreta (p < .01). Antibody titre, heterophil (%(, and phytohemagglutinin (PHA) were significantly higher in birds fed with Zn‐supplemented diets (p < .05). In treatments supplemented with ZnO‐NPs and Zn‐methionine, the SOD activity in the liver, pancreas, and plasma was greater as compared with the other treatments (p < .05). The MDA content in eggs was significantly reduced in groups supplemented with Zn (p < .01). Moreover, dietary Zn supplementation significantly affected serum total protein, albumin, glucose, alkaline phosphatase activity, carbonic anhydrase activity, and Zn level (p < .05). In conclusion, this study demonstrated that dietary supplementation with ZnO‐NPs can improve the performance of laying hens. Therefore, ZnO‐NPs can enhance zinc absorption in the intestine of aged layers and can be a more suitable source of zinc than regular Zn‐oxide in diets.     

Tea polyphenols increase the antioxidant status of laying hens fed diets with different levels of ageing corn

This study was conducted to evaluate the effects of ageing corn levels (stored for 4 years) with or without the supplementation of tea polyphenols (TPP) on the performance, egg quality and antioxidant status of laying hens. A total of 288 Lohmann commercial laying hens (63-week-old) were used under a 2 × 4 factorial arrangement with 4 levels of dietary ageing corn (0%, 25%, 50%, or 100%) and 2 levels of TPP (0 and 600 mg/kg) for 8 wk. Dietary ageing corn linearly decreased (P < 0.05) the egg production, serum total antioxidant capacity (T-AOC), liver glutathione peroxidase (GSH-Px) of laying hens, yolk index, yolk colour, 1,1-diphenyl-2-picrylhydrazyl (DPPH) value and the reducing power value of egg yolk, but it linearly increased (P < 0.05) the feed conversion rate, ovary malondialdehyde (MDA) content of laying hens, and the protein carbonyl content of egg yolk. Tea polyphenol supplementation increased (P < 0.05) the serum T-AOC, serum superoxide dismutase (SOD), liver SOD, liver GSH-Px, ovary SOD, GSH-Px, the expression of antioxidant-related genes of laying hens, albumen height, Haugh unit, DPPH value and the majority free amino acids of egg yolk, but it decreased (P < 0.05) the serum MDA content of laying hens, MDA and protein carbonyl of egg yolk. In conclusion, the ageing corn significantly reduced the performance, egg quality, antioxidant status and egg antioxidant capacity of laying hens, while TPP supplementation partially counteracted the adverse effects, especially antioxidant status and egg antioxidant capacity of laying hens.     

Effects of Chinese herbal mixture on performance,egg quality and blood biochemical parameters of laying hens

The aim of the study was to evaluate the effect of Chinese herbal mixture (CHM) in laying hen diets on performance, egg quality and egg nutrition components, as well as selected blood biochemical parameters. A total of 270 Lohmann Brown laying hens, 24 week of age, were randomly distributed into three dietary treatments and fed for 6 week. The CHM was used at the levels of 0%, 0.5% and 1.0% in the diets of the control and two treatment groups respectively. Each dietary treatment was divided into five replicates, comprising of 18 hens each. Hens were housed in a 3‐tier battery system. Feed and water were provided ad libitum. Blood samples and eggs were collected at the end of the experiment. The results showed that dietary treatments did not affect egg weight, mortality, eggshell thickness, albumen height, Haugh units, eggshell‐breaking strength and egg‐shape index. Dietary supplementation of CHM significantly improved (p < 0.05) laying rate and the lowest feed conversion ratio were observed with 1.0% CHM supplementation diets. CHM supplementation decreased (p < 0.05) cracked‐egg rate, egg yolk cholesterol, blood serum levels of cholesterol, triglyceride, low‐density lipoprotein cholesterol (LDL‐C) and alanine aminotransferase (ALT) and increased blood serum levels of high‐density lipoprotein cholesterol (HDL‐C). No differences in serum total protein, serum albumen, serum glucose and aspartate amino transferase (AST) were observed in hens fed CHM. In conclusion, dietary supplementation with CHM improved egg production and egg quality and reduced serum cholesterol concentrations in laying hens. Dietary supplementation of 1.0% CHM in layer diets may be a feasible means of producing eggs with lower cholesterol and higher egg yolk phospholipid contents for health conscious consumers.     

Effect of different levels of black cumin (Nigella sativa L.) on performance,intestinal Escherichia coli colonization and jejunal morphology in laying hens

This study was conducted to investigate the effects of different levels of black cumin seeds (Nigella sativa L.) on performance, intestinal Escherichia coli count and morphology of jejunal epithelial cells in laying hens. A total of 100 Leghorn laying hens (Hy‐Line W‐36) of 49 weeks old were randomly distributed among five cage replicates of five birds each. Experimental diets consisted of different levels (0%, 1%, 2% and 3% of diet) of dietary black cumin inclusion. The experimental period lasted for a total of 10 weeks, and egg quality indexes and laying hens' performance were measured as two 35‐day trial periods. At the final day, two hens per replicate were slaughtered to investigate the influence of dietary treatments on intestinal E. coli colonization and morphology of jejunal cells. Although dietary black cumin in all supplementation levels decreased (p < 0.05) the enumeration of ileal E. coli, the morphological and histological alterations in small intestine such as enhancement of villus height to crypt depth ratio, increased goblet cell numbers and proliferation of lamina propria lymphatic follicles were observed after dietary supplementation with at least 2% black cumin. Dietary treatments decreased (p < 0.05) the concentration of serum cholesterol and triglycerides and increased (p < 0.05) serum HDL concentration and relative weight of pancreas; however, the egg yolk cholesterol was not influenced by dietary treatments. In addition, dietary supplementation with black cumin improved (p < 0.05) eggshell quality and Haugh unit. The best feed conversion ratio was obtained when diets were supplemented with 2% black cumin. This improvement was due to the increase (p < 0.05) in egg mass and contemporaneous decrease (p < 0.01) in feed consumption. The present results indicated that regardless of supplementation level, dietary inclusion of black cumin decreased E. coli enumeration in ileal digesta and improved serum lipid profile and eggshell quality, whereas the best intestinal health indices and haying hens' performance were obtained by at least 2% black cumin seeds.     

Effects of dietary red yeast (Sporidiobolus pararoseus) on production performance and egg quality of laying hens

The purpose of this study was to evaluate the effect of dietary red yeast (Sporidiobolus pararoseus) on production performance and egg quality of laying hens. A total of 200 Esa Brown laying hens (23 weeks of age) were allocated equally to negative control group (no yeast supplement); positive control group (2 g/kg of Saccharomyces cerevisiae); 0.5, 1, 2 g/kg red yeast respectively. The experiment was lasted for 12 weeks. Feed intake, hen‐day egg production and egg weight were not different between control and supplemented groups. However, yeast‐supplemented groups were significantly improved feed efficiency (p < .05). Incremental levels of red yeast increased the colour score of egg yolk (p < .05). The cholesterol and triglyceride of serum and yolk were significantly (p < .05) lower in the laying hens fed dietary administration red yeast compared to the control diet; however, no significant (p > .05) differences among yeast‐supplemented groups were observed. The hepatic hydroxymethylglutaryl‐coenzymeA (HMG‐CoA) reductase activity was significantly lower (p < .05) in the 2 g/kg red yeast‐supplemented group compared to the control and other red yeast‐supplemented groups. Concentrations of caecal short‐chain fatty acids was increased (p < .05) in laying hens fed 1 and 2 g/kg red yeast as compared to the control group. Dietary administration of 2 g/kg red yeast (S. pararoceus) significantly improved egg yolk colour, decrease serum and egg yolk cholesterol levels.     

Dietary inclusion of dehydrated bocaiuva pulp increases the antioxidant potential of quail eggs

The aim of this study was to evaluate dietary supplementation of different levels of dehydrated bocaiuva pulp (DBP) on the productive performance of laying quails, and on lipid oxidation, and quality in their eggs. A total of 120 quails were distributed in a completely randomized design with six treatments (0%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5% of DBP), five replicates and four birds per experimental unit. To evaluate lipid oxidation, the eggs were collected on five consecutive days at the end of the trial and distributed in a completely randomized experimental design in a 6 × 5 factorial scheme (eggs from quails fed different levels of DBP × evaluated fresh and after 7, 14, 21 and 28 days). The antioxidant potential of diets was improved (p < 0.05) when the DBP was added estimated as 2,2'‐azinobis‐3‐ethylbenzothiazolin‐6‐sulfonic acid (ABTS) free radical scavenging capacity. No effect (p > 0.05) was observed on feed intake, hen‐day egg production and feed conversion (kg/kg and kg/dz). There were no changes (p > 0.05) in the egg weight, Haugh unit, yolk index or eggshell percentage. Although no difference was observed (p > 0.05), when comparing each level with the control, a negative linear effect (p < 0.05) on specific gravity was observed. In addition, only the treatment with 0.5% pulp exhibited lower (p < 0.05) eggshell thickness compared with the control (0%). Thiobarbituric acid reactive substances (TBARS) analysis showed that as the dietary pulp level was increased, malondialdehyde content decreased linearly (p < 0.05) in the egg yolks, regardless of the storage period. Inclusion of DBP in the diets had no effect (p > 0.05) on the concentration of conjugated dienes in the eggs. The diets containing DBP showed a potential antioxidant effect, reducing the degree of lipid oxidation in egg yolk. However, no beneficial effects were observed on performance and egg quality.     

Polyphenols in Eucalyptus leaves improved the egg and meat qualities and protected against ethanol‐induced oxidative damage in laying hens

Polyphenols in Eucalyptus leaves (PE) were value resources due to various pharmacological activities, but data on the effect on laying hens are very scare. This study was conducted to determine the effect of PE on the laying performance, egg traits, meat quality, antioxidant status and liver tissues of laying hens. One hundred and twenty 256‐day‐old Yueqinhuang laying hens were randomly assigned to four treatment groups (different levels of PE at 0, 0.5, 0.8 and 1.2 g/kg diet) for 63 days with 15 replicates per group. Addition of 0.8 g/kg PE not only improved the egg trait by increasing the eggshell thickness and decreasing MDA production and cholesterol content in the egg yolk, but also significantly enhanced meat quality of hens, as suggested by the increase pH_45 min (p < .01) and a* value, and decrease drip loss rate (p < .01). Meanwhile, under acute ethanol‐induced oxidative damage condition, supplementation of 0.8 g/kg PE enhanced the serum antioxidant status by increasing enzymatic activities (GSH‐PX, T‐SOD, T‐AOC), inhibited oxidative damage and provided protective effect to liver tissue. In conclusion, addition of 0.8 g/kg PE not only improved the egg traits and meat quality without obvious adverse effects, but also increased the serum antioxidant status of the hens and protected their liver tissue from ethanol‐induced oxidative damage. This study indicated that PE could be utilized as an effective feed additive for laying hens to improve health performance and egg traits.     

Effects of dietary phytoncides extracted from Korean pine (Pinus koraiensis) cone on performance,egg quality,gut microflora,and immune response in laying hens

This study was conducted to evaluate the effects of dietary phytoncides extracted from discarded Korean pine cones (Pinus koraiensis) on the performance, egg quality, immune response and gut microflora in laying hens. A total of 400 Hy‐Line brown laying hens (50‐week old) were allotted into four dietary treatments including a control diet or a diet supplemented with phytoncides at 0.002%, 0.004% and 0.008%. During the 6 weeks of experimental feeding, 0.008% of dietary phytoncides improved egg production, feed conversion ratio (p < 0.05), but not feed intake, egg weight or feed efficiency. Although dietary phytoncides had no effect on egg quality, decreases in Haugh units depending on storage periods were improved by 0.008% of dietary phytoncides (p < 0.05). To investigate the roles of dietary phytoncides on the alteration of the immune response during inflammation, lipopolysaccharide (LPS) or saline was intraperitoneally injected into 10 hens per diet group on the end date of the experimental feeding period. Serum immunoglobulins and splenic cytokine expression at mRNA levels were then measured at 4 hr postinjection. Although the levels of IgA were decreased by LPS injection in all dietary groups, dietary phytoncides at 0.008% showed a higher level of IgA by LPS (p < 0.05). Interestingly, although LPS injection resulted in an enhanced expression of proinflammatory cytokines such as IL‐1β and IL‐6, dietary phytoncides at 0.008% showed less increased levels of them (p < 0.05). Gut microflora was examined from 10 hens per diet group at the end of the experimental period. While the number of Lactobacillus spp. was increased (p < 0.05), Escherichia coli counts in the cecal contents were decreased by 0.008% of dietary phytoncides. Taken together, these results demonstrate that dietary supplementation of 0.008% phytoncides improved the egg production, immune responses during inflammation and gut microflora in laying hens.     

Influence of sumac (Rhus Coriaria L.) and ginger (Zingiber officinale) on egg yolk fatty acid,cholesterol and blood parameters in laying hens

The aim of the study was to evaluate the potential effect of different levels of sumac (Rhus coriaria L.) seed powder and ginger (Zingiber officinale) root powder on egg yolk fatty acid composition, blood/yolk cholesterol in laying hen. A total of 63 (ATAK‐S: Domestic Turkish Laying Hens) laying hens (average weight: 1470 g each hen, 25‐weeks of age) were assigned to seven treatment diets including sumac seed (S) and ginger root powder (G) at 0 g/kg (control), 10 g/kg (S1), 20 g/kg (S2), and 30 g/kg (S3); 10 g/kg (G1), 20 g/kg (G2), or 30 g/kg in rations respectively, for 8 weeks. After a two‐week adaptation period to cages, the hens were allocated to 7 groups with 9 replicates of 1 hen in per cage each. The replications were allotted equally into the upper and lower cages to minimize the effects of cage level. In this study, egg yolk cholesterol had a decrease (p <0.05) in supplemented diet( sumac seed and ginger root powder). Fatty acid content in yolk; saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acids and rate of n6/n3 were not significant (p <0.05). However, dietary supplementation with sumac and ginger powder reduced and yolk/blood cholesterol concentrations in laying hens. Supplementation of sumac and ginger affected on HDL, there was found a significant effect (p < 0.05) in treatment groups. Moreover, LDL positively decreased in all treatment groups compared with the control group. The findings of this study suggested that feeding sumac and ginger tend to be decreasing cholesterol levels in both yolk and blood on laying hens. It can be concluded that ginger root and sumac seed powder can be used as an effective feed additive to improve fatty acid composition and yolk and blood cholesterol in ATAK‐S laying hens.     

Organic trace minerals on productive performance,egg quality and immune response in Bovans White laying hens

This study was performed in 360 laying Bovans White hens and aimed to evaluate the effect of Carbo‐Amino‐Phosphate‐Chelates (CAFQ) as a mineral premix and its 30% reduction by compared to inorganic trace minerals (ITM) concerning its performance, egg quality, tibia breaking strength and immunity. Sixty‐week‐old hens were assigned into three treatments with 10 replicates of 12 birds each. Treatments were as follows: (a) (100% ITM), (b) (100% CAFQ) and (c) (70% CAFQ). Based on the results obtained during 12 weeks, under the current test conditions, improved yolk colour (p < 0.05); shell breaking strength (p < 0.05); and storage time (p < 0.05) were observed in hens fed with a diet reduced by 70% in CAFQ inclusion showed similar performance behaviour and better egg breaking strength regarding with ITM, suggesting the possibility of minimizing the inclusion of trace minerals in laying hen diets improving environmental impact, in contrast to the use of inorganic sources of minerals.     

Effects of alkaline protease on the production performance,egg quality,and cecal microbiota of hens during late laying period

This study investigated the effects of diet supplementation with alkaline protease (AKP) on the production performance, egg quality, and cecal microbiota of laying hens. A total of 720 Hy-Line Brown laying hens (60 weeks old) were divided into four groups with six replicates of 30 birds each. No AKP was added to the control diet, and the hens in the other three groups (Groups 1, 2, and 3) were fed the basal diet supplemented with AKP preparations at 3, 6, and 9 u/g of diet, respectively. Results showed that AKP supplementation significantly decreased the feed/egg ratio (p < 0.05). Compared with that of the control group, the eggshell strength of Group 1 was significantly increased (p < 0.05), and the egg yolk weight of Groups 1 and 3 was significantly increased (p < 0.05). Distinctive difference in cecal microbiota was observed between AKP and control groups, and the average values of microbial diversity was lower in the AKP group than in the control group. The relative abundance of Bacteroidetes and Firmicutes at the phylum level, Rikenellaceae, Lachnospiraceae, Lactobacillaceae, Erysipelotrichaceae, and Christensenellaceae at the family level, and Rikenellaceae_RC9_gut_Group, Lactobacillus, Romboutsia, Lachnoclostridium, and Blautia at the genus level in the AKP group changed significantly compared with that in the control group (p<0.05).     

Effect of dosage and application mode of l‐carnitine on plasma lipid and egg‐yolk cholesterol of turkeys,hatchability of eggs and post‐hatch growth of their offsprings

The effect of dosage and application mode of l ‐carnitine on plasma lipid and egg‐yolk cholesterol of breeder turkeys, hatchability of eggs and post‐hatch growth response was investigated using 180 breeder hens. The hens were assigned to six dietary treatments in a 2 × 3 factorial arrangements of two application modes of l ‐carnitine (diet and drinking water) supplemented at 0, 50 and 100 ppm (mg/kg or mg/l) levels, respectively. Each treatment was replicated five times with six hens per replicate. Dietary inclusion of 50 ppm l ‐carnitine showed the lowest (p < 0.01) plasma total cholesterol (TC) and low‐density lipoprotein concentration (LDL). Breeder hens offered 50 ppm l ‐carnitine with no regard to application mode recorded the highest (p < 0.01) plasma high‐density lipoprotein (HDL). Hens offered 50 and 100 ppm l ‐carnitine irrespective of application mode also showed reduced (p < 0.01) egg‐yolk TC concentration at 32 weeks of age. Dietary supplementation of 50 ppm l ‐carnitine for breeder turkeys recorded the lowest (p < 0.01) egg‐yolk triglyceride (TG) at 40 weeks of age. Hens offered 50 ppm l ‐carnitine irrespective of application mode recorded the highest (p < 0.05) hen‐day egg production. Incidence of dead‐in‐shell also reduced (p < 0.05) with increasing dosage of l ‐carnitine. Dietary supplementation of 50 ppm and oral application in drinking water of 100 ppm l ‐carnitine for breeder turkeys resulted in highest (p < 0.05) egg fertility. Offsprings from breeder hens fed diets supplemented with l ‐carnitine recorded no post‐hatch mortality. Highest (p < 0.05) post‐hatch final live weight and weight gain was obtained with poults obtained from hens fed diet supplemented with 50 ppm l ‐carnitine. In conclusion, dietary supplementation of 50 ppm l ‐carnitine for turkey hens showed improved serum lipid profile, egg fertility, reduced dead‐in‐shell, egg‐yolk cholesterol and resulted in improved post‐hatch growth performance.     

Effect of dietary supplementation of organic zinc on laying performance,egg quality and some biochemical parameters of laying hens

This study was conducted to evaluate the effects of zinc methionine (Zn‐Met) supplementation on the performance, egg quality, antioxidant status and some biochemical parameters of blood serum in laying hens from 22 to 34 weeks of age. A total of 120 Hisex Brown laying hens of 22‐week‐old were randomly allocated into five treatments with six cage replicates for each (four hens/replicate). Dietary treatments consisted of the basal diet with no Zn‐Met supplementation (control group) and basal diet supplemented with 25, 50, 75 or 100 mg Zn‐Met/kg diet. No significant differences were observed on body weight, body weight gain or feed conversion ratio due to dietary Zn‐Met supplementation. However, highly significant impact was observed on daily feed intake. Egg number, egg weight and egg mass were increased in the group fed diet supplemented with the highest level of Zn‐Met (100 mg/kg of diet) as compared to other groups. All egg quality traits were statistically (p > .05 or .01) affected as a response to dietary Zn‐Met supplementation except egg shape index, shell percentage and yolk index. In comparison with the control group, dietary supplementation of 25, 50, 75 or 100 mg Zn‐Met/kg decreased serum triglyceride and LDL‐cholesterol levels. Serum cholesterol level was increased with all dietary levels of Zn‐Met in comparison with the control group. Dietary Zn‐Met supplementation increased the serum content of zinc, where the highest values were recorded with 50 and 100 mg Zn‐Met/kg diet. Dietary Zn‐Met levels did not affect the antioxidant indices in blood serum except for the activity of copper–zinc superoxide dismutase (Cu‐Zn‐SOD). The activity of Cu‐Zn‐SOD was increased with Zn‐Met supplementations with no differences among supplemental zinc levels. It is concluded that dietary Zn‐Met supplementation reduced serum triglyceride, LDL‐cholesterol and increased Zn status and resulted in promoting antioxidant ability of laying hens, and the addition of 100 mg Zn‐Met/kg to layer diet was appropriate for improving the above parameters in addition to egg production indices and Haugh unit score.     

Effects of cerium oxide supplementation to laying hen diets on performance,egg quality,some antioxidant enzymes in serum and lipid oxidation in egg yolk

This study was conducted to determine the effects of dietary cerium oxide levels (0, 100, 200, 300 or 400 mg/kg) on the laying performance, egg quality, some blood serum parameters and egg lipid peroxidation of laying hen. In total, one hundred and twenty 22‐week‐old brown Lohman LSL laying hens were randomly assigned to five groups equally (n = 24). Each treatment was replicated six times. Dietary supplementation of cerium oxide had no significant effect on feed intake and egg weight. The addition of cerium oxide to the laying hens' feed improved feed conversion ratio and increased (p < 0.05) egg production. Quality criteria of egg for except shell breaking strength were not affected by supplementing cerium oxide. In particular, supplementation of 200 and 300 mg/kg cerium oxide to the laying hens feed led to a significant (p < 0. 01) increase in egg shell breaking strength. Calcium and phosphorus concentration of serum increased significantly (p < 0.05) with supplementation of 100 mg/kg cerium oxide to laying hen diets. It was also observed that serum superoxide dismutase (SOD) activity and malondialdehyde (MDA) concentration decreased significantly with supplementation of cerium oxide in diets. Inclusion of cerium oxide resulted in a significant reduction in thiobarbituric acid reactive substance (TBARS) values in egg yolk in this study. It can be concluded that the addition of cerium oxide had positive effects on egg production, feed conversion ratio and egg shelf life. Based on the results of this study, it could be advised to supplement laying hens feed with cerium oxide as feed additives.     

Rare earth element‐enriched yeast improved egg production and egg quality in laying hens in the late period of peak egg production

The objective of this study was to determine the effects of rare earth element‐enriched yeast (RY) on egg production, coefficient of total tract apparent digestibility (CTTAD), egg quality, excreta gas emission and excreta microbiota of laying hens. A total of 216 ISA brown laying hens of 52 weeks of age were used in a 5‐week feeding trial and data were collected every week. Birds were randomly allotted to three dietary treatments each with six replicates and 12 hens per replicate. Each cage (38 cm width × 50 cm length × 40 cm height) contained one hen. Treatments consisted of corn–soya bean meal‐based diet supplemented with 0, 500 or 1000 mg/kg of RY. From weeks 55 to 56, inclusion of RY linearly increased (p < 0.05) egg production. The CTTAD of nitrogen was increased (linear, p < 0.05) with increasing dietary level of RY. In week 55, yolk height and Haugh units were increased linearly (p < 0.05) with increasing dietary RY content. However, no significant effects were observed in terms of excreta emissions and excreta microbiota in laying hens. In conclusion, dietary supplementation with RY improved egg production and CTTAD of nitrogen and slightly improved egg quality in laying hens of the late period of peak egg production.     

Impact of supplementing diets with propolis on productive performance,egg quality traits and some haematological variables of laying hens

One hundred and twenty eight, 28‐weeks‐old Lohmann LSL hybrid layers were used in this experiment, which lasted 12 weeks to investigate the effect of propolis supplementation on the productive performance, egg quality traits and haematological variables of laying hens. All hens were randomly classified into four equal experimental groups, eight replicates (4 birds/each). Hens in group 1 were fed on a commercial diet and considered as control group, while those in groups 2, 3 and 4 were fed on the same commercial diet and supplemented with 250, 500 and 1000 mg propolis/kg diet. The obtained results revealed that daily feed consumption/hen increased insignificantly with increasing propolis level than that of the control group. Regarding the means of egg mass and egg production rate, it was observed that the laying hens fed diets containing 250 and 1000 mg propolis/kg significantly (p < 0.05) produced more and heaver egg in comparison with control group. External egg quality traits have not affected with increasing the level of propolis, while eggshell weight was significantly (p < 0.05) increased. The internal egg quality traits except albumen and yolk percentages increased significantly (p < 0.05) with increasing propolis level for treated hens as compared to those in the control. Concerning the haematological parameters, the results showed that the levels of total protein and globulin increased significantly with increasing propolis level, while cholesterol and liver enzymes were significantly decreased (p < 0.05). Heterophils count of hens in the treated groups significantly decreased, whereas the lymphocyte count significantly increased, resulting in a decreased H/L ratio than that of the control group. Thus, it could be concluded that the supplementation of 250 mg propolis/kg diet is highly recommended to improving egg production, blood constituent and haematological parameters of the commercial laying hens.     

Effects of dietary resveratrol supplementation during gestation and lactation of sows on milk composition of sows and fat metabolism of sucking piglets

The purpose of this article was to investigate the effects of dietary resveratrol supplementation during gestation and lactation of sows on the milk composition of sows and the fat metabolism of sucking piglets. Forty sows were allotted to two experimental treatment groups that included the following: (a) control sows (CON treatment, n = 20) fed with a corn–soybean meal control diet and (b) treatment sows (RES treatment, n = 20) fed with a control diet with addition of 300 mg/kg resveratrol. The results showed that the content of lactose in the colostrum was increased (p < 0.05) and the content of fat in 21‐day milk was increased (p < 0.05) by dietary resveratrol supplementation. In the RES treatment group, the concentrations of high‐density lipoprotein‐cholesterol (HDL‐C), low‐density lipoprotein‐cholesterol (LDL‐C), lipase activity and insulin (INS) in plasma of sucking piglets were increased (p < 0.05). In the adipose tissue, the enzyme activities of hormone‐sensitive lipase (HSL), acetyl‐CoA carboxylase (ACC) and lipoprotein lipase (LPL) increased significantly by RES treatment (p < 0.05), and the mRNA levels of acetyl coenzyme A‐alpha (ACCα), LPL, fatty acid transport protein (FATP1) and CCAAT–enhancer‐binding protein gene (C/EBPα) were higher in the RES treatment group (p < 0.05). In conclusion, resveratrol supplementation on gestational and lactating sows improved the content of lactose in the colostrum and the content of fat in milk at day 21 of lactation. In addition, resveratrol supplementation on sows increased HDL and LDL in the plasma of piglets. In piglet adipose tissue, the enzyme activity and mRNA level related to lipolysis, fatty acid uptake from circulating triacylglycerols and lipogenesis are partially improved by resveratrol supplementation on sows. These aspects affect fat metabolism in piglets.     

Dietary methionine requirement of Jing Brown layer hens from 9 to 17 weeks of age

This study was conducted to evaluate the effect of dietary methionine (Met) supplementation in growth performance and reproductive performance of Jing Brown layer hens. A total of 375 9‐week‐old Jing Brown layer hens were allocated equally to five treatments consisting of 5 replicates with 15 hens. Hens were fed with a diet of corn and soya bean meal supplemented with 0.23%, 0.27%, 0.31%, 0.35% and 0.39% Met respectively. Different Met levels did not significantly affect average daily feed intake (ADFI), average daily gain (ADG) and feed/gain ratio (F/G) (p > 0.05), whereas flock uniformity (FU) and jejunum index were significantly different (p < 0.05), and the largest FU was observed in 0.31% Met. Dietary supplementation of Met significantly affected reproductive system development (p < 0.05), and 0.27–0.31% Met obtained optimal reproductive system development. Different Met levels significantly affected serum uric acid and alkaline phosphatase. Moreover, the relatively higher reproductive hormones in serum were observed in 0.27% Met. Analysis of quadratic curve estimation of flock uniformity, the total number of follicles, the primary follicles and the secondary follicles showed that the optimal Met levels were 0.293%, 0.286%, 0.286% and 0.288%, which could be averaged to 0.288%. These results suggested that the optimal Met requirement for Jing Brown layer hens from 9 to 17 weeks old is 0.29%.     

Montmorillonite improved the intestinal mucosal barrier functions of laying hens in late production

This study was conducted to investigate the effects of dietary supplementation with montmorillonite (MMT) on performance, intestinal endotoxin concentration, gut mucosal oxidation status, intestinal morphology and permeability, and immunological barrier function of laying hens during late production. Four hundred and eighty 75‐week‐old laying hens (Lohmann Brown) were randomly assigned to five treatments with eight replicates per treatment and 12 hens in each replicate. The hens were fed the basal diet supplemented with 0 (control), 0.3, 0.6, 0.9, or 1.2 g MMT/kg for 70 days. Compared with the control, supplemented with 0.9 g MMT/kg increased egg mass significantly (p < 0.05) during weeks 1–5 of the experiment. Supplemented with 0.6 and 0.9 g MMT/kg also increased the endotoxin concentration in the ileal digesta (p < 0.05), but decreased the MDA concentration in the ileum significantly (p < 0.05). The T‐AOC in the jejunum of the group fed 0.3 g MMT/kg was significantly increased (p < 0.05). Compared with the control, the villus height:crypt depth of ileum from the groups fed 0.6, 0.9, and 1.2 g MMT/kg increased significantly (p < 0.05). The sIgA concentration of jejunum in the groups fed 0.6 and 0.9 g MMT/kg was higher (p < 0.05) than the control. The MMT supplementation linearly increased (p < 0.05) the mRNA expression of claudin‐1 and claudin‐5 in the jejunum. Dietary MMT supplementation down‐regulated the mRNA expression of NF‐κB P65 and TNF‐α in the jejunum in a linear and quadratic manner (p < 0.05). The IL‐1β mRNA expression of jejunum in the group fed 0.6 g MMT/kg was lower (p < 0.05) than the control. In conclusion, dietary supplementation with MMT may improve the gut barrier functions and suggests that 0.9 g/kg of MMT in diets may be the optimal supplemental level for laying hens in late production.     

Effect of dietary threonine on laying performance and intestinal immunity of laying hens fed low‐crude‐protein diets during the peak production period

Threonine (Thr) may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine laying performance, and the intestinal immune function of laying hens provided diets varying in digestible Thr levels. Lohmann Brown laying hens (n = 480), 28 weeks of age, were allocated to six dietary treatments, each of which included five replicates of 16 hens. Dietary crude protein (CP) 16.18% diet was offered as the positive control diet. L‐Thr was added to the negative diet (14.16% CP) by 0, 1.0, 2.0, 3.0 and 4.0 g/kg, corresponding 0.44%, 0.43%, 0.49%, 0.57%, 0.66% and 0.74% digestible Thr. At 40 weeks, a reduction in CP level decreased laying performance (p < 0.05). In the low CP, increasing dietary Thr increased (p < 0.05) egg production and egg mass and rose to a plateau between 0.57% and 0.66%. The hens fed 0.66% Thr showed the lowest value (p < 0.05) of feed conversion ratio (FCR). Serum level of uric acid showed the lowest values (p < 0.05) at 0.57–0.66%. In addition, serum‐free Thr maximized (p < 0.05) between 0.66% and 0.74%. Digestive trypsin activity decreased (p < 0.05) when hens fed the low‐CP diet compared with hens fed CP (16.18%) and hens fed 0.57–0.66%. Expressions of ileal MUC2 mRNA maximized (p < 0.05) at 0.66% Thr. Occludin mRNA increased with increasing Thr level (p < 0.05). sIgA mRNA reached to the maximum level (p < 0.05) at 0.66% and 0.74% Thr. INF‐γ mRNA reached to the lowest level (p < 0.05) at 0.65%. Expressions of ileal IL‐2, IL‐6, IL‐1β mRNA decreased with increasing Thr level (p < 0.05). In conclusion, Thr supplementation resulting in optimal laying performance and stimulated the mucosal immune system, suggesting that it is a limiting amino acid in the low‐crude‐protein diet of laying hens during the peak production period.