ß-Casomorphin increases fat deposition in broiler chickens by modulating expression of lipid metabolism genes.

ß-Casomorphin is an opioid-like bioactive peptide derived from ß-casein of milk that plays a crucial role in modulating animal's feed intake, growth, nutrient utilization and immunity. However, the effect of ß-casomorphin on lipid metabolism in chickens and its mechanism remain unclear. The aim of this study was to investigate the effects of ß-casomorphin on fat deposition in broiler chickens and explore its mechanism of action. A total of 120 21-day-old Arbor Acres male broilers (747.94±8.85 g) was chosen and randomly divided into four groups with six replicates of five birds per replicate. Three groups of broilers were injected with 0.1, 0.5 or 1.0 mg/kg BW of ß-casomorphin in 1 ml saline for 7 days, whereas the control group received 1 ml saline only. The results showed that subcutaneous administration of ß-casomorphin to broiler chickens increased average daily gain, average daily feed intake and fat deposition, and decreased feed : gain ratio (P<0.05). The activity of malate dehydrogenase in the pectoral muscle, liver and abdominal adipose tissue was also increased along with the concentrations of insulin, very-low-density lipoprotein and triglyceride in the plasma (P<0.05). The activity of hormone-sensitive lipase in the liver and abdominal adipose tissue and the concentration of glucagon in the plasma were decreased by injection with ß-casomorphin (P<0.05). Affymetrix gene chip analysis revealed that administering 1.0 mg/kg BW ß-casomorphin caused differential expression of 168 genes in the liver with a minimum of fourfold difference. Of those, 37 genes are directly involved in lipid metabolism with 18 up-regulated genes such as very low density lipoprotein receptor gene and fatty acid synthase gene, and 19 down-regulated genes such as lipoprotein lipase gene and low density lipoprotein receptor gene. In conclusion, ß-casomorphin increased growth performance and fat deposition of broilers. Regulation of fat deposition by ß-casomorphin appears to take place through changes in hormone secretion and enzyme activities by controlling the gene expression of lipid metabolism and feed intake, increasing fat synthesis and deposition.

Effects of flavones of sea buckthorn fruits on growth performance, carcass quality, fat deposition and lipometabolism for broilers.

The objective of this study was to evaluate the effects of different levels of flavones of sea buckthorn fruits (FSBF) on growth performance, carcass quality, fat deposition, and lipometabolism for broilers. 240 one-day-old Arbor Acres male broilers were randomly allotted to 4 dietary treatments (0, 0.05%, 0.10%, and 0.15% FSBF) with 6 replicates of 10 birds. Broilers were reared for 42 d. Results showed FSBF quadratically improved average daily feed intake (ADFI), average daily gain (ADG), and final body weight (BW) (P = 0.002, P = 0.019 and P = 0.018, respectively). The abdominal fat percentage in 0.05%, 0.10%, and 0.15% FSBF supplementation groups was decreased by 21.08%, 19.12%, and 19.61% with respect to the control group, respectively (P < 0.05). The intramuscular fat (IMF) content in the breast muscle of the broilers was increased by 7.21%, 23.42% and 6.30% in 0.05%, 0.10% and 0.15% FSBF groups, and that in the thigh meat was raised by 4.43%, 24.63% and 12.32%, compared with the control group, respectively (P < 0.05). FSBF had a quadratic effect on the abdominal fat percentage and IMF in the breast muscle (P < 0.05). Dietary FSBF also modified fatty acids of muscular tissues, resulting in a higher ratio of unsaturated to saturated fatty acids (P < 0.05). Supplementing FSBF in the diet greatly decreased the levels of triglyceride, cholesterol, and low-density lipoprotein cholesterol (P < 0.05). Moreover, the quadratic responses were also observed in the levels of insulin and adiponectin in serum (P = 0.020 and P = 0.037, respectively). Abdominal fat percentage was correlated negatively with insulin and positively with adiponectin (P < 0.05). IMF content in the breast and thigh muscles were correlated positively with insulin, and negatively with adiponectin (P < 0.05). A positive correlation existed between breast muscle, IMF, and leptin (P < 0.05). In conclusion, adding FSBF into the diets affected growth performance and fat deposition of broilers by regulating lipometabolism. Fat deposition and distribution of broilers were closely associated with concentrations of insulin and adiponectin. The optimal level of FSBF supplemented in diet was 0.05 to 0.10% in this study.

Effects of glucocorticoid-induced stress on absorption of glycylsarcosine in jejunum of broilers.

This study was conducted to investigate the effects of stress on the absorption of glycylsarcosine in the jejunum of broilers, as well as the underlying mechanisms. A glucocorticoid analogue, dexamethasone (DEX), was chosen to simulate the effects of endogenous glucocorticoids. Two hundred 21-day-old male Arbor Acre broilers were randomly allotted to 4 groups with 5 replicates in each group and 10 birds per replicate by a completely randomized assignment involving a single factorial arrangement of injection dose DEX. The broilers were injected with 1-mL DEX (0.1-, 0.5-, and 2.5-mg/kg BW) or saline subcutaneously in the abdomen 1×/d for 7 d. The broilers were weighed, killed, and sampled at 28 days old. The results showed that DEX dose-dependently reduced growth and endogenous corticosterone content in the plasma of the broilers (P<0.05). DEX decreased absorption of glycylsarcosine by jejunum brush border membrane vesicles and gut sacs (P<0.05). DEX treatment increased the crypt depth of the jejunum, decreased the villus height, absorption area, and ratio of villus height to crypt depth (P<0.05). Effect of dexamethasone on villus width was not obvious (P>0.05). It was concluded that DEX reduced the absorption of glycylsarcosine in the jejunum of broilers.

Attempts to increase inosinic acid in broiler meat by using feed additives.

To explore regulation of inosinic acid content in chicken meat as a result of feed additives, 576 one-day-old male Arbor Acres broilers were randomly allotted into 8 dietary treatments including control, purine nucleotide (P), betaine (B), soybean isoflavone (S), purine nucleotide + betaine (PB), purine nucleotide + soybean isoflavone (PS), betaine +soybean isoflavone (BS), and purine nucleotide + betaine + soybean isoflavone (PBS) by a 2 × 2 × 2 factorial arrangement. At d 42 of age, broilers were slaughtered, and growth performance, carcass characteristics, inosinic acid content, and activities of enzyme closely related to inosinic acid metabolism of broilers were measured. The results revealed that these feed additives did not affect ADG and ADFI of the broilers (P > 0.05). However, supplementing purine nucleotides lowered feed/gain of broilers in PS and PBS groups (P < 0.05). There was a significant interaction on feed/gain of broilers between purine nucleotides and soybean isoflavone (P < 0.05). The abdominal fat percentages in groups B, S, BS, and PBS were lower than the control group, respectively (P < 0.05). The thigh muscle percentages of groups P and B were higher than that of group PB (P < 0.05). There were certain interactions on the percentage of thigh muscle (P = 0.05) and abdominal fat (P < 0.05) between P, B, and S groups. Compared with the control group, inosinic acid content in broiler breast meat was improved by using feed additives (P < 0.05). Supplementing purine nucleotides, betaine, soybean isoflavone, and their combinations increased alkaline phosphatase activity in breast meat of broilers (P < 0.05). Purine nucleotides improved the activity of adenosine deaminase, but decreased the activity of 5'-nucleotidase. Soybean isoflavone lowered the activity of alkaline phosphatase. There were no significant interactions on activities of creatine kinase, adenosine deaminase, alkaline phosphatase, and 5'-nucleotidase between these additives (P > 0.05). The umami rating of broiler breast meat increased in conjunction with supplementing these additives. In conclusion, supplementing standard feed with the additives investigated in this study could improve inosinic acid content in chicken meat by increasing synthase activity or inhibiting degradation enzyme activity without inferior growth performance and carcass quality.

Hypothalamic protein profiles associated with inhibited feed intake of ducks fed with insufficient dietary arginine.

An experiment was conducted to investigate the effect of arginine on feed intake regulation. One hundred and twenty six 1-day-old male White Pekin ducks (Anas platyrhynchos domestica) were randomly were allotted to one of two dietary treatments. The birds were fed diets containing 0.71% (deficient) or 1.27% (sufficient) arginine for 3 weeks. At 21 days of age, feed intake was determined and hypothalamic protein profiles were analyzed using isobaric tags for relative and absolute quantification technique. The birds fed with arginine-deficient diet had a lower final live BW and cumulative feed intake (P1.5-fold expressional changes between arginine-deficient and -sufficient dietary treatments. Nine of these proteins were upregulated and seven of them were downregulated. The identified proteins could be regrouped into six categories: protein processing, carbohydrate metabolism and energy production, transporter, cytoskeleton, immunity and neuronal development. Dietary arginine deficiency decreased expression of proteins involved in energy production (glycine amidinotransferase, aldolase B fructose-bisphosphate, aconitase, transaldolase, 6-phosphofructokinase type C-like) and oxygen transportation (haemoglobin subunit α expression). The proteomic alterations described here provides valuable insights into the interactions of arginine with appetite.

Application of mineral bed materials during fast pyrolysis of rice husk to improve water-soluble organics production.

Fast pyrolysis of rice husk was performed in a spout-fluid bed to produce water-soluble organics. The effects of mineral bed materials (red brick, calcite, limestone, and dolomite) on yield and quality of organics were evaluated with the help of principal component analysis (PCA). Compared to quartz sand, red brick, limestone, and dolomite increased the yield of the water-soluble organics by 6-55% and the heating value by 16-19%. The relative content of acetic acid was reduced by 23-43% with calcite, limestone and dolomite when compared with quartz sand. The results from PCA showed all minerals enhanced the ring-opening reactions of cellulose into furans and carbonyl compounds rather than into monomeric sugars. Moreover, calcite, limestone, and dolomite displayed the ability to catalyze the degradation of heavy compounds and the demethoxylation reaction of guaiacols into phenols. Minerals, especially limestone and dolomite, were beneficial to the production of water-soluble organics.

Effects of stress simulated by dexamethasone on jejunal glucose transport in broilers.

Twenty-four 21-d-old Arbor Acres (AA) broilers with similar BW were randomly assigned into 4 groups to investigate the effects of stress on the absorption of glucose in the intestine of broilers and its mechanisms. In this study, dexamethasone (DEX), an analog to glucocorticoid secreted when animals suffer from stress, was chosen to simulate the effects of glucocorticoid. Broilers were injected subcutaneously with 0, 0.1, 1, or 5 mg of DEX/kg of BW into the abdomen for 7 d. To explain the nonspecific regulation of glucocorticoid on glucose transport of the jejunum in broilers, the effects of DEX on the jejunum mucosa morphology and disaccharidase activities in broilers were investigated. The results showed that DEX restrained the growth of broilers, and the extent of restraint increased with the increase of the dose of DEX (P<0.05). However, the activities of sucrase and maltase in the jejunum of the broilers injected with DEX were not different from those of the control broilers (P>0.05). In addition, DEX increased the crypt depth of jejunum in broilers, and decreased the villus height, absorption area, and villus height/crypt depth ratio significantly (P<0.05), whereas DEX had no significant effect on villus width and the thickness of mucosa lamina propria (P>0.05). To clarify the specific regulation of glucocorticoid on the glucose transport of jejunum in broilers, the absorption of glucose by jejunum brush border membrane vesicles (BBMV) was investigated, and the expression of Na+-dependent glucose transporter (SGLT1) mRNA was detected by real-time PCR. The results showed that DEX significantly inhibited the glucose absorption of jejunum BBMV (P<0.05), and the extent of inhibition depended on the dose of DEX. In addition, DEX decreased the expression of SGLT1 mRNA significantly (P<0.05). According to these data, we concluded that DEX restrains the glucose transport of jejunum in broilers through nonspecific and specific regulations.

Efficacy of phytases on egg production and nutrient digestibility in layers fed reduced phosphorus diets.

The effects of phytases on the performance of layers and the ileal nutrient digestibility of corn-, soybean-, and by-product meal-based diets were assessed with 320 Hy-Line brown layers from 23 to 28 wk of age. Layers were grouped randomly into 5 treatments, with 8 replicates per treatment and 8 layers per replicate. The 5 diets consisted of a positive control diet with adequate Ca (3.30%), total P (0.50%), and nonphytate P (NPP; 0.28%), and a negative control diet with Ca reduced by 0.12%, total P reduced by 0.14%, NPP reduced by 0.13%, and 3 phytases (phytase A derived from Aspergillus niger, and phytases B and C derived from Escherichia coli) supplemented at 300 phytase units/kg of feed, respectively. Egg production and feed intake were recorded daily, and eggshell quality and ileal nutrient digestibility were measured at the end of a 6-wk feeding period. The results revealed that the reduction of Ca and P from the positive control diet significantly depressed feed intake, egg mass, eggshell hardness, and the digestibility of N, Ca, P, and amino acids (P < 0.05). Phytase supplementation in the negative control diet improved the digestibility of P and Ca by 11.08 and 9.81% (P < 0.05), respectively, whereas it improved the digestibility of amino acids by 2 to 8% (P < 0.05). However, the digestibility of most amino acids was not restored to the levels of the positive control diet by the application of phytases. Supplementing phytases in the negative control diet improved the rate of lay, egg mass, and egshell quality to the levels of birds fed the positive control diet. These results suggest that supplementing phytases can improve the digestibility not only of Ca and P, but also of amino acids in layers fed a corn-, soybean-, and by-product-based diet.