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.     

Expression of follistatin is associated with egg formation in the oviduct of laying hens

The objective of this study was to examine the expression profiles of follistatin (FST) and its associated molecules (MSTN, INHA, INHBB, INHBA, ACVR2A, and ACVR2B) in the oviduct of laying hens at 3 hr and 20 hr post‐ovulation (p.o., n = 5; 35 weeks old), molting (n = 5; 60 weeks old), and non‐laying (n = 4; 35–60 weeks old) hens and also to localize the FST by using immunohistochemistry assay. Expression of FST was significantly higher (p < .05), and MSTN was lower in the uterus of laying hens around 15–20 hr p.o. (during eggshell formation), however, their expressions in the magnum remain unchanged across different physiological stages of hens. FST was mainly expressed in the luminal and glandular epithelium of the uterine tissues, and their expression intensity was highest in laying hens during the eggshell mineralization. There was a relatively increased expression of INHA in the magnum of laying hens around 3 hr p.o. as compared to non‐laying and molting hens. At the same time (3 hr p.o.), there was a significant (p < .05) decrease in the expression of the INHBB, ACVR2A, and ACV2B. These results indicate that follistatin may regulate the differentiation of uterine luminal and glandular epithelium during eggshell biomineralization.     

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.     

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.     

Astragalus polysaccharide supplementation improves production performance,egg quality,serum biochemical index and gut microbiota in Chongren hens

This research aimed to determine whether the astragalus polysaccharide (AP) can improve the production performance and gut microbiota in Chongren hens.120 Chongren hens (240-d old) were randomly allocated into 4 treatments with 30 hens and fed with a control basal diet (CON) or CON supplemented with the different levels of AP (100, 200, and 400 mg/kg) for 56 d. The egg production and feed conversion ratio were decreased (p < .05) with the levels of AP. The yolk weight, yolk color, eggshell thickness, eggshell redness index and egg shell yellowness were increased (p < .05). AP supplementation increased CAT and T-AOC and SOD, and decreased MDA (p < .05). Supplementation of AP decreased IL-2, IL-6 and TNF-α levels (p < .05), but increased the IL-4 level in the liver (p < .05). The villus heights of duodenum, jejunum ileum, the crypt depth and V/C in the jejunum were increased (p < .05). Dietary supplementation of 200 mg/kg AP increased (P relative abundances of Firmicutes and Lactobacteriaceae in the cecum of Chongren hens. In conclusion, addition of AP improved the production performance, egg quality, antioxidant function, and intestinal morphology in hens, which might be associated with the gut microbiota.     

Effect of dietary inclusion of cumin seed oil on the performance,egg quality,immune response and ovarian development in laying hens under high ambient temperature

The objective of the present study was to find the effect of cumin seed oil (CSO, Cuminum cyminum L.) on the laying performance, ovarian follicular development and immune response in laying hens under high ambient temperature. A total of 162 Boven hens were randomly divided into three treatments and were fed, ad libitum, diets containing 0 (control), 250 or 500 g CSO per ton from 24 to 30 weeks of age. The experiment was done during summer season where the average temperate was 30 to 36°C. Feed intake and egg mass were recorded. Egg quality characteristics and egg‐yolk cholesterol content were evaluated. Ovary and oviduct samples were immediately weighted, and ovarian follicles were classified. Plasma total protein, albumin, total cholesterol, LDL‐cholesterol, HDL‐cholesterol glutamic oxalacetic transaminase (GOT), and glutamate pyruvate transaminase (GPT) were measured. Yolk width, yolk weight, yolk colour, shell weight and shell thickness were increased by feeding CSO. Egg production rate was not affected. However, dietary 500 g CSO per ton had a significantly positive impact on egg weight in comparison with control. The FCR was improved by feeding 500 g CSO per ton; however, feed intake and egg mass were not affected by CSO treatments. Plasma GOT, GPT and triglycerides were significantly decreased, while, plasma HDL‐cholesterol was significantly (p < .05) increased due to CSO treatments. Yolk cholesterol content was significantly decreased; however, liver malondialdehyde (MDA) concentration was insignificantly decreased due to dietary treatments. Interestingly, the inclusion of CSO in laying hens’ diets improved the antibody titres against Newcastle disease (ND, p < .05) and against avian influenza H9N1 (p > .05) when compared with the control diet. It could be concluded that dietary inclusion of CSO improved egg weight, FCR, yolk and shell quality characteristics and did not have a negative effect on the reproductive morphology parameters in laying hens.     

Comparison of selected indices of internal environment and condition of laying hens kept in furnished cages and in aviaries

Biochemical and hematological examination of blood and individual assessment of the birds were performed in Lohman Brown laying hens at 45 weeks of age housed in different systems. The biochemical examination revealed higher (p < .01) corticosterone levels, creatine kinase, and aspartate aminotransferase activity and lower (p < .01) levels of lactate, triglycerides, albumin, calcium, and phosphorus in aviary hens compared to hens housed in furnished cages. Hematological examination of hens housed in aviaries revealed higher (p < .05) hematocrit, leukocytes, heterophils, eosinophils, basophils, monocytes, and H/L ratio. Furthermore, hens housed in aviaries had lower (p < .01) body weight than hens in furnished cages, they were worse feathered (p < .001), had more damaged combs (p < .05), and poorer physical condition (p < .01). In contrast, caged hens showed worse (p < .01) feather condition of the wings due to abrasion and claws due to overgrowth. The results have shown that the housing system has a significant impact on the internal environment and condition of birds and that housing in aviaries without taking into account the specifics of such housing may lead to significant stress and disturbance to the welfare of laying hens.     

Effects of nanocalcium carbonate on egg production performance and plasma calcium of laying hens

This experiment was conducted to evaluate the effects of nanocalcium carbonate (NCC) instead of calcium carbonate (CC) on egg production, egg weight, egg mass, FCR, blood calcium and egg quality characteristics in laying hens. A total of 120 laying hens were used in a 10‐weeks trial, from week 23 to 33 of age. Laying hens were randomly assigned to six treatments with four replications, five hens each. The experimental treatments involved replacing 50% of the CC in the diet by decreasing amounts of NCC and were T1 Basal diet (BD) with 8.06% CC; T2 (6.045% of CC as a negative control); T3 (4.03% of CC replaced by 2.015% NCC); T4 (4.03% of CC replaced by 1.01% NCC); T5 (4.03% of CC replaced by 0.252% NCC) and T6 (4.03 of CC replaced with 0.126%NCC).Egg weight was unaffected by dietary treatments (p > .05). However, the egg production percentage and egg mass in T6 were less than that of other treatments (p < .05). The laying hens in the control group had the best average feed conversion ratio (p < .05). Also, the lowest concentration of calcium in hens’ blood was recorded for birds fed T6 (p < .05). The best egg shell quality (relative egg shell weight and egg shell weight/surface) was observed in T1 (p < .05).Collectively, our results demonstrated that NCC could replace CC at a lower inclusion level but extreme reduction of calcium concentration in diets (to 1.43% Ca in the T6 group) reduced production performance, egg quality characteristics, Tibia thickness and blood calcium of laying hens.     

The impact of phytoestrogen source supplementation on reproductive performance,plasma profile,yolk fatty acids and antioxidative status in aged laying hens

The objectives of this study were to investigate the effects of flaxseeds and/or fenugreek seeds as a source of phytoestrogens in laying feed on productive performance, egg quality, yolk fatty acids, plasma profile and antioxidative status in aged laying hens. A total of 120 Bovans Brown hens at 65 weeks of age were housed individually in laying cages in an open‐sided building under a 16‐hr light: 8‐hr dark lighting schedule. Hens were randomly divided into four experimental treatments (n = 30 each): (a) control (basal diet without any supplementation); (b) 1 g/kg of flaxseeds; (c) 1 g/kg of fenugreek seeds; and (d) combination of 1 g/kg flaxseeds and 1 g/kg fenugreek seeds from 65 to 71 weeks of age. Hen‐day egg production and egg mass were significantly increased by dietary supplementation of flaxseeds and/or fenugreek seeds, while feed intake was not affected; thus, feed conversion ratio was improved (p < 0.05). Weights of egg, albumen, yolk and shell were increased by the dietary treatments. Shell thickness and yolk colour were improved by supplementation of flaxseeds and/or fenugreek seeds. Yolk crude protein was not significantly affected by treatments; however, crude fat and calcium contents in yolk were increased and egg yolk cholesterol content was decreased. Interestingly, dietary supplementation of flaxseeds, fenugreek seeds and their combination had a significant positive effect on plasma luteinizing hormone, follicle‐stimulating hormone, oestradiol‐17β and triglycerides. Inclusion of flaxseeds and/or fenugreek seeds in the diets enhanced the serum glutathione peroxidase and superoxide dismutase activities and reduced the malondialdehyde and total cholesterol concentrations in plasma. Dietary supplementation of flaxseeds and/or fenugreek seeds increased α‐linolenic and linoleic acids in egg yolk. It could be concluded that inclusion of mixed sources of phytoestrogens in diets improved laying performance, egg quality, the antioxidative status, hormonal profile and steroidogenesis in aged laying hens.     

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.     

Efficacy of essential oils combination on performance,ileal bacterial counts,intestinal histology and immunocompetence of laying hens fed alternative lipid sources

This study was carried out to assess the effects of a blend of herbal essential oils (namely Thymus vulgaris, Mentha piperita, Rosmarinus offisinalis and Anethum graveolens) and different dietary lipid sources on the performance, ileal bacterial enumeration, intestinal histological alterations and immune responses in laying hens. For this purpose, a total of 150 laying hens were randomly allocated to six experimental treatments with five replicates of five birds each. Dietary treatments consisted of three levels of a mixture of essential oils (0, 100 and 200 mg/kg) and two sources of lipid (soybean oil and fish oil containing different ratios of n‐6 to n‐3 fatty acids) fed to the animals during an 80‐days feeding trial. Findings indicated that dietary administration of fish oil not only increased significantly the spleen relative weight (p < 0.01) and the antibody titre against Newcastle virus (p < 0.05) but also led to reductions in liver relative weight (p < 0.05) and feed conversion ratio (p < 0.05). Moreover, the mixture of herbal essential oils brought about declines in hepatic relative weight, heterophile to lymphocyte ratio (p < 0.05) and intestinal pathogen populations (p < 0.01). Mention must also be made of the improvements it made in spleen weight (p < 0.01), antibody titres against SRBC (p < 0.01) and Newcastle virus (p < 0.05), villus height to crypt depth ratio (p < 0.01), goblet cell numbers (p < 0.05), lamina propria lymphatic follicle diameters (p < 0.01) and feed conversion ratio (p = 0.06). It may be claimed that the enhancements observed in the performance of laying hens fed fish oil and 200 mg/kg of the blend of essential oils could have potentially been associated with improved intestinal health indices as well as cellular and humoral immune responses.     

Effect of dietary l-carnitine supplementation and energy level on oxidant/antioxidant balance in laying hens subjected to high stocking density

This study aimed to investigate the effect of l -carnitine and energy level and on oxidant/antioxidant balance in laying hens subjected to high stocking density. A total of 176, 32-week-old laying hens were assigned to eight groups with four replicates and hens in four groups were placed at the normal stocking densities of 500 cm²/hen (four hens per cage) and in the remaining four groups were placed at the high stocking densities of 287.5 cm²/hen (seven hens per cage). Hens received diets of high (2,850 kcal/kg ME) or normal (2,650 kcal/kg ME) energy which are supplemented with 0 or 200 mg/kg l -carnitine for 70 days. Results showed that exposure to high stocking density increased (p < .05) plasma malondialdehyde (MDA) and nitric oxide (NO) levels and decreased (p < .05) erythrocyte superoxide dismutase (SOD), catalase (CAT) and superoxide dismutase (GPx) activities. l -carnitine supplementation increased (p < .05) erythrocyte SOD, CAT and GPx activities, and decreased (p <.05) MDA and NO level in high stocking densities. The oxidan/antioxidan balance of birds was not influenced by increasing dietary energy level. The results of the present study indicate that the supplementation of l -carnitine to the birds subjected to high stocking density could effectively reverse the negative effects of high stocking density by improving oxidant/antioxidant balance. Therefore, l -carnitine supplementation at level of 200 mg/kg to diet may be as a favourable alternative to deal with oxidative stress caused by high stocking density in laying hens.     

Effects of vitamin E supplementation on performance,serum biochemical parameters and fatty acid composition of egg yolk in laying hens fed a diet containing ageing corn

This study investigated whether dietary vitamin E (VE) supplementation could alleviate any detrimental effects of ageing corn in the diet for laying hens on egg performance, egg quality, serum biochemical parameters, cholesterol content and the fatty acid (FA) profile of egg yolks. The experiment consisted of a 2 × 3 factorial design with two corn types (normal corn and ageing corn) and three concentrations of VE (0, 20 and 100 IU/kg). A total of 216 Lohmann laying hens (50‐week‐old) were randomly allocated into six treatment diets for 12 week. Each treatment had six replicates with six hens. The results showed that ageing corn significantly reduced average daily feed intake (ADFI; p < 0.01) and egg weight (p < 0.05). Dietary VE supplementation had no significant influences on egg production performance (p > 0.05). Egg yolk colour was decreased in ageing corn diets (p < 0.01), while 20 and 100 IU/kg VE significantly improved vitelline membrane strength (p < 0.01) compared with feeding of 0 IU/kg VE. Ageing corn also significantly decreased the content of cholesterol including total cholesterol (TC; p < 0.05), low density lipoprotein cholesterol (LDL‐C; p < 0.01) and very low density lipoprotein cholesterol (VLDL‐C; p < 0.05) in the serum. Feeding 100 IU/kg VE significantly increased the content of LDL‐C (p < 0.01) and VLDL‐C (p < 0.05) in the serum. Furthermore, the content of the oleic acid, docosahexaenoic acid and total monounsaturated fatty acid (MUFA) was lower (p < 0.05) and stearic acid and total saturated fatty acid (SFA) was higher (p < 0.05) in egg yolks in ageing corn diets. Ageing corn resulted in reduced feed intake, egg weights and yolk colour, but the effects of VE supplementation were independent of those of age of corn and were unable to counteract the negative effects of feeding ageing corn.     

Influence of Substituting Dietary Soybean for Air‐Classified Sunflower (Helianthus annuus L.) Meal on Egg Production and Steroid Hormones in Early‐Phase Laying Hens

Soybean meal (SBM) is the most widely and expensive protein source used in the formulation of poultry diets; however, when the price of SBM increases, poultry nutritionists seek alternative sources that are more economical in formulating least‐cost rations. This research aimed to evaluate the effects of dietary air‐classified sunflower meal (SFM) on some productive parameters and plasma steroid hormones in laying hens. In this trial, 20‐week‐old laying hens (ISA Brown strain) in the early phase of production were randomly assigned to two groups and fed wheat middlings‐based diets containing soybean (135 g/kg; 48% CP) or air‐classified SFM (160 g/kg; 41% CP) as the main protein source. Laying performance, egg size and feed conversion ratio were evaluated for 10 week. Plasma steroid hormones (progesterone and oestradiol) in the hens were quantified weekly. Substituting SBM with air‐classified SFM did not change (p > 0.05) the hens' growth performance, whereas feed consumption and efficiency were positively influenced (p < 0.05) by SFM treatment. Egg production rate was improved in hens fed the SFM diet (p < 0.05), as well as the percentage of medium‐size eggs that was higher for SFM treatment (p < 0.05). Steroid hormones levels were affected by dietary treatment (p < 0.01). From our findings, it could be effective to include air‐classified SFM in early‐phase laying hen diets as an alternative protein source substituting SBM, without negative influence on productive performance and egg traits, reducing also the production costs.     

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.     

Effects of iron glycine chelate on laying performance,antioxidant activities,serum biochemical indices,iron concentrations and transferrin mRNA expression in laying hens

This study was conducted to evaluate the effects of iron glycine chelate (Fe‐Gly) on laying performance, antioxidant enzyme activities, serum biochemical indices and iron concentrations in laying hens. A total of 810 laying hens (Hy‐Line Variety White, 26 weeks old) were randomly assigned to six groups with five replicates of 27 layers. Hens in the control group received diet supplemented with 60 mg Fe/kg as FeSO₄, while hens in other five groups received the diet supplemented with 0, 20, 40, 60 and 80 mg Fe/kg from Fe‐Gly respectively. The results showed that dietary Fe‐Gly treatments significantly influenced (p < 0.01) the laying rate and egg weight of layers, compared with the control group. Concerning to CuZn‐superoxide dismutase (CuZn‐SOD) and total superoxide dismutase (T‐SOD) activity, Fe‐Gly groups (60, 80 mg Fe/kg) were promoted significantly (p < 0.01) compared with 0 mg Fe/kg group. The concentrations of Fe in serum, liver, kidney, spleen and ovary were increased significantly with the level dietary Fe‐Gly raised where Fe‐Gly groups (60, 80 mg Fe/kg) had observably higher Fe concentration than the control (p < 0.01) in serum, kidney and spleen. There was a trend that transferrin mRNA expression was decreased with the increase of Fe as Fe‐Gly in diets, and compared with the control, the expression was lower in the group fed diet with 60 mg/kg Fe as Fe‐Gly. In conclusion, Fe‐Gly (60 mg Fe/kg) had improved laying rate, egg weight, SOD enzyme activity, Fe absorption and protein synthesis in body and promoted iron metabolism in laying hens. Moreover, Fe‐Gly (40 mg/kg Fe) had the similar effect with control group. It revealed that FeSO₄ could be substituted by lower concentration of Fe‐Gly and Fe‐Gly may be superior to FeSO₄ for iron fortification to laying hens.     

Effect of protease derived from Pseudoalteromonas arctica supplementation on growth performance,nutrient digestibility,meat quality,noxious gas emission and blood profiles in finishing pigs

This study was conducted to evaluate the effects of dietary supplementation of protease derived from Pseudoalteromonas arctica (PPA) in finishing pigs. A total of 160 pigs were used in this 10‐week trial. Dietary treatment groups were as follows: CON (basal diet); TRT1 (basal diet + 0.1% PPA); TRT2 (basal diet + 0.2% PPA); and TRT3 (basal diet + 0.3% PPA). During weeks 1–5, pigs fed with different levels of PPA‐supplemented diet showed linear increase (p < .05) in the apparent total tract digestibility (ATTD) of nitrogen (N) and linear decrease (p < .05) in the concentrations of serum total protein. During weeks 6–10, pigs fed with different levels of PPA‐supplemented diet showed a linear decrease in feed conversion ratio (p < .05). During the overall period, there was a linear decrease in feed conversion ratio (p < .05) associated with the inclusion of PPA. Pigs fed diets with 0.2% PPA supplementation had lower (p < .05) feed conversion ratio than those fed CON diet during weeks 6–10 and the overall period, and had higher (p < .05) ATTD of N than those fed CON diet during weeks 1–5. Pigs fed diets with PPA supplementation had lower (p < .05) concentrations of serum total protein than those fed CON diet on week 5. In conclusion, dietary supplementation with PPA diet has beneficial effects on growth performance, nutrient digestibility, backfat thickness and the concentrations of serum total protein.     

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.