Effects of Quercetin on Performance and Lipid Metabolism in Laying Hens

Quercetin has a variety of biological activities. However, its application as a feed additive in poultry production is limited. In this study, the effects of quercetin on performance and lipid metabolism in Hessian laying hens were investigated and the possibility of quercetin to decrease cholesterol in eggs and Low Density Lipoprotein cholesterol（LDL-cholesterol） in laying hens were explored. A total of 240 laying hens at 29-week-old were randomly assigned to four treatments, with six replicates of 10 birds per replicate. The treatments were fed with basal diet supplemented with 0, 0.2, 0.4 and 0.6 g · kg-1 quercetin for 8 weeks. Layer performance, lipid concentration in livers, yolks and serum were measured at the end of the experiment. The results showed that laying rate had a quadratic correlation with the level of quercetin（p=0.056） and was maximized by the supplement level of 0.2 g · kg-1 diet. When the level of dietary quercetin increased, feed-egg ratio decreased. Crude fat and the total cholesterol of livers decreased by supplementation of quercetin. The total cholesterols of yolks also decreased and had a quadratic correlation with the levels of quercetin（p=0.019）. Insulin increased by supplement of quercetin. In conclusion, quercetin improved the performance and reduced egg yolk cholesterol by affecting serum hormone levels.

Effect of Quercetin on Egg Quality and Components in Laying Hens of Different Weeks

This trial was conducted to evaluate the effect of quercetin on egg quality and components in laying hens of different weeks. A total of 240 healthy Hessian laying hens at 29, 39-week-old with similar body weight and laying rate were randomly divided into four groups with six replicates of 10 each replicate, respectively. The treatments were fed with basal diet supplemented with 0, 0.2, 0.4 and 0.6 g-kg-1 quercetin for 8 weeks. The results showed that compared with the control, broken or soft shell rate significantly decreased at 0.2 and 0.4 g.kg-1 quercetin and eggshell thickness significantly increased at 0.4 g.kg-1 quercetin （P〈0.01） in laying hens at 39-47 weeks old; yolk protein significantly decreased at 0.6 g kg-1 quercetin （P〈0.05） in laying hens at 29-37 weeks old; while yolk protein significantly increased at three quercetin treatments in laying hens at 39-47 weeks old; yolk cholesterol significantly decreased by quercetin in laying hens at 29-37 weeks old （P〈0.05）; yolk total phospholipids significantly increased at 0.4 and 0.6 g kg-1 quercetin （P〈0.01） and yolk cholesterol significantly decreased at 0.6 g kg-1 quercetin （P〈0.05） in laying hens at 39-47 weeks old. In a word, quercetin affected egg quality and components to some extents in laying hens of different weeks, the older the hens became, the better improvement they would be. The optimum level of quercetin was 0.4 g kg-1 in the basal diet.

Correlation Between Cholesterol Content in Egg Yolks and Laying Rate

[Objectives]This study was conducted to investigate the relationship between cholesterol content in egg yolks and laying rate of laying hens.[Methods]Forty eight 450-day-old Hyline brown hens with uniform weight were randomly divided into 4 groups with 3 replicates in each group and 4 individuals in each replicate.Group 1 as the control check group(CK)was fed the basal diet;group 2 was fed the basal diet with the addition of 150 g/t of probiotics;group 3 was the basal diet+200 g/t lipase group;and group 4 was fed the basal diet with the addition of 150 g/t of probiotics and 200 g/t of lipase.The preliminary trial period was 10 d,and the experimental period was 30 d.[Results]The cholesterol content in the egg yolks of each test group was higher than that of the control group at 14 and 28 d after the drug administration.The laying rate of each test group began to increase at 14 d after the drug administration;and the laying rate of each test group increased significantly 28 d after the drug administration.It indicated that with the increase of cholesterol in egg yolks,the laying rate of laying hens increased significantly.[Conclusions]This study provides a certain experimental basis for culture production of laying hens.

Hepatic steatosis is associated with dysregulated cholesterol metabolism and altered protein acetylation dynamics in chickens

Background Hepatic steatosis is a prevalent manifestation of fatty liver, that has detrimental effect on the health and productivity of laying hens, resulting in economic losses to the poultry industry. Here, we aimed to systematically investigate the genetic regulatory mechanisms of hepatic steatosis in laying hens.Methods Ninety individuals with the most prominent characteristics were selected from 686 laying hens according to the accumulation of lipid droplets in the liver, and were graded into three groups, including the control, mild hepatic steatosis and severe hepatic steatosis groups. A combination of transcriptome, proteome, acetylome and lipidome analyses, along with bioinformatics analysis were used to screen the key biological processes, modifications and lipids associated with hepatic steatosis.Results The rationality of the hepatic steatosis grouping was verified through liver biochemical assays and RNA-seq. Hepatic steatosis was characterized by increased lipid deposition and multiple metabolic abnormalities. Integration of proteome and acetylome revealed that differentially expressed proteins(DEPs) interacted with differentially acetylated proteins(DAPs) and were involved in maintaining the metabolic balance in the liver. Acetylation alterations mainly occurred in the progression from mild to severe hepatic steatosis, i.e., the enzymes in the fatty acid oxidation and bile acid synthesis pathways were significantly less acetylated in severe hepatic steatosis group than that in mild group(P < 0.05). Lipidomics detected a variety of sphingolipids(SPs) and glycerophospholipids(GPs) were negatively correlated with hepatic steatosis(r ≤-0.5, P < 0.05). Furthermore, the severity of hepatic steatosis was associated with a decrease in cholesterol and bile acid synthesis and an increase in exogenous cholesterol transport.Conclusions In addition to acquiring a global and thorough picture of hepatic steatosis in laying hens, we were able to reveal the role of acetylation in hepatic steatosis and depict the changes in hepatic cholesterol metabolism. The findings provides a wealth of information to facilitate a deeper understanding of the pathophysiology of fatty liver and contributes to the development of therapeutic strategies.

Olive Cake in Laying Hen Diets for Modification of Yolk Lipids

The possibility of improving egg yolk lipids of laying hens by olive cake （OC） feeding was investigated. Forty-two, 54-week-old, Lohman laying hens were fed for 12 weeks on 3 diets formulated to contain 0, 28.5 or 57 g OC/kg. Plasma cholesterol, triglycerides and high-density lipoproteins （HDL） were determined. Also total lipids, triglycerides, cholesterol, low-density lipoproteins （LDL）, Phospholipids and fatty acids were determined in egg yolk. Olive cake feeding at 28.5 or 57 g/kg diet decreased cholesterol and triglycerides of plasma, without affecting HDL. It also decreased total lipids, triglycerides, cholesterol, LDL and Phospholipids of yolk （P 〈 0.001）. Total （monounsaturated fatty acids, MUFA） was decreased with OC feeding at 28.5 g/kg diet, while it was increased with the 57 g/kg dietary OC. The two levels of OC decreased total （saturated fatty acids, SFA） but increased total （polyunsaturated fatty acids, PUFA）, n-6 PUFA, and n-3 PUFA of egg yolk, compared to the control. Thus, according to the results of the present experiment feeding hens 57 g OC/kg diet lowers cholesterol and total SFA and increases total MUFA, total PUFA, total n-3 PUFA and docosahexanoic acid in egg yolk.

Effects of Probiotics and Enzyme Preparation on Cholesterol, Triglyceride and Serum ALT and POD in Egg Yolks

[Objectives]This study was conducted to investigate the effects of probiotics and enzyme preparation on cholesterol,triglyceride and serum alanine aminotransferase (ALT) and peroxidase (POD) in egg yolks.[Methods]Forty eight 450-day-old Hyline brown hens were randomly divided into 4 groups with 3 replicates in each group and 4 individuals in each replicate.Group 1 as the control check (CK) group was fed the basal diet;group 2 was fed the basal diet with the addition of 150 g/t of probiotics;group 3 was the basal diet +200 g/t lipase group;and group 4 was fed the basal diet with the addition of 150 g/t of probiotics and 200 g/t of lipase.The preliminary trial period was 10 d,and the trial period was 30 d.[Results]The contents of cholesterol and triglyceride in the egg yolks of the test groups supplemented with the probiotics and enzyme preparation were higher than those of the CK.On the 14^th day of treatment,the cholesterol contents in the egg yolks of group 2 and group 4 were significantly higher than that of group 1 ( P <0.05).On the 28^th day of treatment,the contents of cholesterol and triglyceride in the egg yolks of the three test groups were significantly higher than those in group 1 ( P <0.05).There were no significant differences in serum ALT and POD between various groups ( P >0.05).[Conclusions]The addition of probiotics and enzyme preparations to the feed of laying hens can increase the contents of cholesterol and triglyceride in egg yolks,without significantly affecting serum ALT and POD.

Effects of Dried Black Cumin and Tamarind Supplementation on Egg Performance and Lipids Concentration in Egg Yolk of Layer Hens

This study was aimed to determine the effects of dried black cumin and tamarind supplementation on egg performance and lipids concentration in egg yolk of layer hens. Sixty laying hens at the age of 18-34 weeks were divided into 4 treatments （control, 1% black cumin, 4% tamarind and 1% black cumin ＋ 4% tamarin in diets） with 4 replications each （15 birds/replication）. The experimental treatments were subjected to completely randomized design. Feed and drinking water were provided ad-libitum. 16 h per day for lighting program during experimental period. The results found that feed efficiency ratio, egg production and egg weight were no significant between treatments. However, average daily feed intake was highest in 4% tamarind and 1% black cumin ＋ 4% tamarin in diets. Egg yolk color score, yolk index, white index and shell tickness were no significantly different, However, haugh unit was lowest in control group. Egg yolk lipids concentration was founded that black cumin and tamarind in diet were reduced cholesterol and triacyl-glycerol concentration with statistical significance （P 〈 0.05）. So that dried black cumin and tamarind supplementation in diets were no any effect on egg production and egg weight. Furthermore, egg yolk cholesterol and triacyl-glycerol concentration were decreased. Hence, supplementation of dried black cumin and tamarind in diets could benefit to consumer health.

Effect of supplementing layer hen diet with phytogenic feed additives on laying performance, egg quality, egg lipid peroxidation and blood biochemical constituents

This study was conducted to evaluate the effects of supplementing laying hen diet with phytogenic additives on laying performance, egg quality, blood constituents and egg lipid peroxidation. Two hundred Lohmann Brown Lite laying hens were randomly allotted to 4 dietary treatments: control(without phytogenic additive), fennel seeds(5 g/kg), black cumin seeds(5 g/kg) and hot red pepper(5 g/kg).Each of the 4 diets was fed to 5 replicates of 10 hens for 8 weeks. No significant differences were observed in body weight or feed intake between the groups. Dietary inclusion of fennel followed by red pepper improved(P < 0.05) egg weight, egg production, egg mass and feed conversion ratio compared with control. Higher yolk shape index, shell and albumen weight percentages and Haugh unit(P < 0.05)were recorded in the fennel supplemented group compared with control. The egg yolk color score increased by the addition of fennel or hot red pepper in laying hen diets compared with control. The inclusion of black cumin or hot red pepper decreased serum and egg yolk cholesterol and malondialdehyde concentrations(P < 0.05) compared with control. Serum aspartate aminotransferase concentration was lower in black cumin group(P < 0.05) than in other treatments. In conclusion, the best laying performance and egg quality were obtained by dietary inclusion of fennel, followed by hot red pepper and black cumin. Dietary supplementation of black cumin or red pepper may lead to the development of low-cholesterol concentration and better antioxidant capacity of eggs.

Analysis of Influencing Factors in Production of Selenium-enriched Eggs

Selenium is an essential trace element for human health.Eating selenium-enriched eggs is conducive to easily and effectively solving the problem of selenium deficiency.In the production process of selenium-enriched eggs,different selenium sources,additive doses,feeding time,and the addition of other vitamins,trace elements,and methionine in the diet will influence the deposition of selenium in eggs.Through this review,it is intended to provide a reference for the practical,safe and economical production of selenium-enriched eggs.