The effect of epigallocatechin gallate on laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of laying ducks reared in high temperature condition.

Epigallocatechin gallate (EGCG) is a main component in green tea extract, which possesses multiple bioactivities. The present research studied the effects of EGCG on the laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of Linwu laying ducks reared under high temperature. A total of 180 42-w-old healthy Linwu laying ducks were allocated into control or EGCG-treated groups. Each treatment had 6 replicates with 15 ducks in each replicate. Diets for the two groups were basal diets supplemented with 0 or 300 mg/kg EGCG, respectively. All ducks were raised in the high temperature condition (35 ± 2 °C for 6 h from 10:00 to 16:00, and 28 ± 2 °C for the other 18 h from 16:00 to 10:00 the next day) for 21 days. Results showed that EGCG increased the egg production rate (p = 0.014) and enhanced the immunocompetence by improving serum levels of immunoglobulin A (p = 0.008) and immunoglobulin G (p = 0.006). EGCG also fortified the antioxidant capacity by activating superoxide dismutase (p = 0.012), catalase (p = 0.009), and glutathione peroxidase (p = 0.021), and increasing the level of heat-shock protein 70 (p = 0.003) in laying ducks' liver. At the same time, hepatic metabolomics result suggested that EGCG increased the concentration of several key metabolites, such as spermidine (p = 0.031), tetramethylenediamine (p = 0.009), hyoscyamine (p = 0.026), ß-nicotinamide adenine dinucleotide phosphate (p = 0.038), and pantothenic acid (p = 0.010), which were involved in the metabolic pathways of glutathione metabolism, arginine and proline metabolism, ß-alanine metabolism, and tropane, piperidine, and pyridine alkaloid biosynthesis. In conclusion, 300 mg/kg dietary EGCG showed protection effects on the laying ducks reared in high temperature by improving the immune and antioxidant capacities, which contributed to the increase of laying performance of ducks. The potential mechanism could be that EGCG modulate the synthesis of key metabolites and associated metabolic pathways.

Effects of rosemary extract supplementation in feed on growth performance, meat quality, serum biochemistry, antioxidant capacity, and immune function of meat ducks.

This study aimed to investigate the effects of diets supplemented with different levels of rosemary extract (RE) on the growth performance, meat quality, serum biochemistry, antioxidative capacity, and immunological capacity of Cherry Valley meat ducks. A total of 525 healthy Cherry Valley female meat ducks at 1 d of age were selected for this study. Ducks were randomly divided into 5 treatments with 7 replicates per treatment, and each replicate had 15 ducks. All replicates were randomly assigned to treatments. The study was designed as a dose response experiment. Treatment 1 (CON) was fed with the basal diet, and Treatment 2 to 5 (RE250, RE500, RE750, RE1000) were fed with the basal diet supplemented with 250, 500, 750, and 1,000 g/t RE, respectively. The whole experiment lasted 42 days with early stage (1-21 d) and late stage (22-42 d). Results showed that during 22 to 42 d, ducks that were fed over 500 g/t RE had significantly lower feed gain ratio than the ones in CON (P = 0.006). In addition, ducks in RE750 had significantly lower L* and a* in leg muscle compared with the ones in CON (P < 0.05). Besides, ducks that were fed between 250 and 750 g/t RE had significantly lower total protein level in serum compared with the ones in CON (P = 0.005). Ducks in RE250 and RE750 had significantly lower albumin, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels in serum compared with the ones in CON and RE1000 (P < 0.05), and significant quadratic relationships were noticed between albumin, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol and dietary RE level (P < 0.05). Moreover, ducks that were fed between 500 and 750 g/t RE had significantly higher levels of interleukin-2 in serum compared to the ones in CON and RE1000 (P = 0.003). Ducks in RE250 and RE750 had significantly higher levels of immunoglobulin G in serum compared to the ones in CON and RE1000 (P < 0.001). Ducks that were fed over 500 g/t RE had significantly higher levels of immunoglobulin A in serum compared to the ones in CON (P = 0.001). Finally, ducks that were fed between 500 and 750 g/t RE had significantly higher serum levels of glutathione peroxidase, superoxide dismutase, catalase, and total antioxidant capacity (P < 0.05) compared to the ones in CON. Ducks that were fed over 250 g/t RE had significantly lower serum level of malondialdehyde compared to the ones in CON (P = 0.020). Collectively, dietary supplementation of RE improved the growth performance and meat qualities of meat ducks during 22 to 42 d, which were possibly associated with the antioxidative and anti-inflammatory effects of RE. Based on the serum antioxidative and immunological parameters, we suggested that 500 to 750 g/t was the optimal supplementation rate for RE in diets for meat ducks aged 22 to 42 d.

Multi-omics reveals host metabolism associated with the gut microbiota composition in mice with dietary ε-polylysine.

This study aimed to assess the influence of dietary supplementation of ε-polylysine on the gut microbiota and host nutrient metabolism, which is not systematically discussed by multi-omics analysis. A total of 40 mice were randomly divided into two groups exposed to either a basal diet (AIN-76A) or a basal diet with 150 ppm ε-polylysine. Fecal samples were collected for gut bacteria identification. Liver and plasma samples were collected for metabolomic and proteomic analyses. The results showed that ε-polylysine decreased the body weight of mice and affected the presence of certain types of intestinal microorganisms. The richness of the microbiota and number of phyla increased with age. ε-Polylysine affected the presence of genera and species, and either regulated or took part in the metabolism of energy, nitrogen, amino acids, lipids, carbohydrates, glycans, cofactors, and vitamins. The metabolite profiling showed that lipid and lipid-like molecules metabolites occupied the majority percent of plasma and liver metabolites. Additionally, ε-polylysine regulated the key role of metabolites and related metabolic enzymes in the metabolic pathways, especially phospholipid metabolism. In conclusion, dietary ε-polylysine improved the immunity of growing mice, and had a greater effect on the anabolism of nutrients in adult mice.

Effects of a mixture of mono-glycerides of butyric-, capric-, and caprylic acid with chlortetracycline on the growth performance, intestine morphology, and cecal microflora of broiler birds.

This study aimed to investigate the effects of a mixture of mono-glycerides of butyric-, capric-, and caprylic acid (MMG) on the growth performance, intestinal morphology, and cecal microflora of broilers. A total of 960 male Arbor Acre broilers were offered basal diets with or without Chlortetracycline additive (CA) at 500 g/t, and MMG at 3,000, 1,000, or 650 g/t, with 8 replicates of 20 birds per treatment. The results confirmed 500 g/t CA with/without 1,000 g/t MMG increased the average daily weight gain (ADG) of birds compared to the control group 1 during the 42-d experimental period (P < 0.05). Comparing to the control group 1, 500 g/t CA with either 650 g or 1,000 g/t MMG or 1,000 g MMG alone increased the ADG of birds during the late growth stage (22-42 d) (P < 0.05). On d 42, the serum triglyceride levels were higher (P < 0.05) in groups supplemented with CA and CA + 1,000 g/t MMG comparing to the control group; while urea nitrogen level was higher in the control group comparing to the rest of treatment groups Compared to the control group 1, 1,000 g/t MMG alone without CA decreased the abundance of Faecalibacterium and Bacteroides but increased the abundance of Escherichia/Shiegella. About 500 g/t CA alone treatment group had higher abundance of Lactobacillus comparing to the rest of groups. In conclusion, dietary supplement with MMG showed beneficial efficacy on the growth and intestinal function of broilers, demonstrating the potential value of MMG to poultry industry. In terms of dosage, the current trial shows that 3,000 g/t (1-21 d) and 1,000 g/t (22-42 d) MMG without CA was the appropriate dietary supplemented rate for broilers. And the mixed use of 500 g/t CA and 1,000 g/t MMG was benefit for broilers at 22 to 42 d.

Optimization of exogenous carbohydrases supplemented in broiler diets using in vitro simulated gastrointestinal digestion and response surface methodology.

The present study aimed to explore the optimal zymogram of combination of 6 carbohydrases (glucoamylase, pullulanase, maltase, thermostable α-amylase, medium temperature α-amylase, and cold-active α-amylase) supplemented in corn-soybean based diet of broilers aged 1 to 3 wk for the maximum starch digestibility, by using in vitro simulated gastrointestinal digestion and response surface method. The third generation of simulated monogastric animal digestion system was used for in vitro digestion experiment. By using single factor completely random design, the optimal supplement levels of single carbohydras were determined by the reducing sugar release amount and improved dry matter digestibility, which were the parameters representing the starch digestibility of the diet. Additionally, Box-Behnken response surface method was used to predict the optimal combination of 6 carbohydrases. The results showed that the optimistic zymogram of 6 carbohydrases in corn-soybean based diet for broilers aged 1 to 3 wk were 297.39 U/g glucoamylase, 549.72 U/g pullulanase, 3.01 U/g maltase, 1,455.73 U/g thermostable α-amylase, 278.64 U/g medium temperature α-amylase, and 1,985.97 U/g cold-active α-amylase, and the associated reduced sugar release amount and improved dry matter digestibility were 215.98 mg/g, and 6.23%, respectively. Furthermore, we conducted in vitro digestion experiments with diets supplemented with the predicted optimistic zymogram and found that the experimental reduced sugar release amount and improved dry matter digestibility were 219.26 mg/g and 6.31% respectively, whose errors to the predicted optimistic reducing sugar release amount and the improved dry matter digestibility were 1.05% and 1.02%. To sum up, the predicted optimal zymogram of 6 carbohydrases in the present study were capable to improve the starch digestibility in diet for broilers aged 1 to 3 wk, which were represented by increased reduced sugar release amount and improved dry matter digestibility.

Evaluation of serum antioxidative status, immune status and intestinal condition of Linwu duck challenged by lipopolysaccharide with various dosages and replications.

The present study investigated the dosage and replication effects of lipopolysaccharide challenges on the serum oxidative and immune status, and the intestinal morphology and permeability of Linwu ducks at the growing stage. A total of 500 54-day-old Linwu ducks were randomly assigned into 10 treatments, which included a factorial arrangement of 2 levels of LPS challenge replications (1 and 2 times) × 5 levels of lipopolysaccharide challenging dosages (0, 0.1, 0.2, 0.4, and 0.8 mg/kg). Each treatment consisted of 5 cages and 10 ducks per cage. The results showed significant replication effects of LPS on the body weight gain of ducks, that 2 replicates of LPS challenges significantly decreased the body weight gain than one challenge (P = 0.036). Regarding to the serum oxidative and immune status, dosage effects of lipopolysaccharide were found on the serum levels of superoxide dismutase (P = 0.034) and immunoglobulin A (P = 0.007), that 0.4 mg/kg lipopolysaccharides significantly increased the levels of these 2 parameters. Additionally, replication effects were found in the serum levels of interlukin 1ß, that 2 replicates of LPS challenges significantly increased the interlukin 1ß levels comparing to one challenge (P = 0.010). Regarding to the intestinal conditions, dosage effects of lipopolysaccharides were found on the ratio of villus height and crypt depth (P = 0.005) in duodenum, and the wall thickness of duodenum (P = 0.010) and jejunum (P = 0.001), that lipopolysaccharides at 0.1, 0.2, and 0.8 mg/kg significantly deteriorated the intestinal morphologies, especially in the duodenum and jejunum. Moreover, the dosage effects of lipopolysaccharides and the interactions of dosages and replications significantly influenced the permeabilities of the intestinal segments (P < 0.05). It appeared that 2 replicates of lipopolysaccharides at the dosage at 0.4 mg/kg could trigger oxidative and immunological stress, and damage the intestinal morphology and permeability of Linwu ducks at the growing stage.

Dietary Supplementation of ε-Polylysine Beneficially Affects Ileal Microbiota Structure and Function in Ningxiang Pigs.

Intestinal microbiota plays an important role in the health of animals. However, little is known about the gut microbiota in Ningxiang pigs. Thus, we investigated how dietary supplementation with different ε-polylysine concentrations (0, 20, 40, 80, and 160 ppm) affected the ileal microbiota in Ningxiang pigs using a replicated 5 × 5 Latin square method. Each experimental period included 10 days for diet adaptation, 3 days for feces collection and 2 days for digesta collection. The ileal contents were collected and used for sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. The results revealed that ε-polylysine significantly decreased the digestibility of crude protein and crude fiber, as well as the utilization of metabolizable energy (P < 0.05). The relative abundances of 19 bacterial genera significantly increased, while those of 26 genera significantly decreased (P < 0.05). In addition, ε-polylysine increased the abundance of some bacteria (e.g., Faecalibacterium, Bifidobacterium, and lactic acid bacteria) and inhibited some other bacteria (e.g., Micrococcaceae, Acinetobacter, Anaerococcus, Peptoniphilus, Dehalobacterium, Finegoldia, Treponema, and Brevundimonas). Furthermore, based on the 16S rRNA gene data and data from the precalculated GreenGenes database, bacterial communities in the ileal contents exhibited enhanced functional maturation, including changes in the metabolism of carbohydrates, amino acids (e.g., alanine, lysine, tryptophan, cysteine, and methionine), cofactors, and vitamins (e.g., biotin, thiamine, and folate), as well as in the activity of the insulin signaling pathway. This study suggests that ε-polylysine may influence the utilization of feed nutrients by Ningxiang pigs, including proteins, lipids, metabolizable energy, and fiber, by regulating the gut microbiota.

Magnolol additive improves carcass and meat quality of Linwu ducks by modulating antioxidative status.

Magnolol rich in Magnolia officinalis is a bioactive polyphenolic compound. The aim of this study was to clarify the effects of magnolol additive (MA) on carcass and meat quality, biochemical characteristics and antioxidative capacity of Linwu ducks, by comparing it to that of antibiotic additive (colistin sulphate, CS). A total of 275 49-d-old ducks were randomly assigned to 5 groups with 5 cages of 11 ducks each and fed by the diets supplemented with 0, 100, 200 and 300 mg of MA/kg and 30 mg of CS/kg for 3 weeks, respectively. The results revealed that MA administration not only increased dressed percentage (calculated as a percentage of live weight), percentage of breast muscle, leg muscle and lean meat (calculated as a percentage of eviscerated weight), but also remarkably increased a*45 min and pH45 min of leg muscle. Moreover, MA administration decreased the percentage of abdominal fat (calculated as a percentage of eviscerated weight), 45-min cooking loss, water loss rate of leg muscle, 45-min cooking loss and drip loss of breast muscle at 24 hr and 48 hr. Furthermore, MA administration enhanced the activities of superoxide dismutase and catalase in serum or liver, serum total antioxidant capacity and hepatic reduced glutathione concentration significantly, compared with the basal diet or CS group (p < .05). On the other hand, triglyceride, total cholesterol, aspartate aminotransferase, malondialdehyde, protein carbonyl and 8-hydroxy-2'-deoxyguanosine contents in serum and liver were significantly increased in Linwu ducks fed with CS, compared with MA groups (p < .05). Taken together, these data demonstrated that magnolol could effectively improve the carcass and meat quality of Linwu ducks by regulating the in vivo antioxidant status and would be a potential candidate to replace antibiotic.

Effects of dietary grape seed polyphenols supplementation during late gestation and lactation on antioxidant status in serum and immunoglobulin content in colostrum of multiparous sows1.

The aim of this study was to determine the effects of dietary grape seed polyphenols (GSP) supplementation during the late gestation and lactation period on reproductive performance, antioxidative status in serum, nutrient composition, and Ig content in colostrum of multiparous sows. On day 80 of gestation, a total of 64 sows with similar body condition were allocated to a completely randomized block design with 4 dietary treatments (n = 16 sows per treatment): 1) basal diet (CON, control group); 2) basal diet supplemented with 200 IU/kg vitamin E (200VE, positive control group); 3) basal diet supplemented with 200 mg/kg GSP (200GSP); and 4) basal diet supplemented with 300 mg/kg GSP (300GSP). The trial lasted 56 d until the piglets were weaned on day 21 of lactation. Reproductive performance, parameters of antioxidative status, and levels of progesterone (P4) and estradiol (E2) in serum, nutrient composition, and Ig content in colostrum of sows were determined. The number of dead fetuses was reduced, and farrowing survival was significantly improved in the litters from 300GSP-fed (P < 0.05). Preweaning survivability significantly increased in the litters from sows fed 200GSP and 200VE (P < 0.05). The activity of superoxide dismutase and glutathione peroxidase (GSH-Px) in the serum was significantly increased in sows fed 200GSP and 300GSP (P < 0.05). The activity of GSH-Px in the serum also significantly increased in sows fed 200VE (P < 0.05). Sows fed 300GSP had the greatest levels of P4 and E2 in the serum, which was significantly greater than sows fed 200VE and CON (P < 0.05). No significant differences were found among treatments for the content of solids-not-fat, fat, protein, and lactose in colostrum (P > 0.05). However, sows fed GSP had greater IgM and IgG content in colostrum compared with sows fed 200VE and CON (P < 0.05). In conclusion, dietary GSP supplementation during late gestation and lactation improved the farrowing survival and preweaning survivability, enhanced the antioxidant status and hormone levels in serum, and increased the IgM and IgG content in colostrum of sows.

Transcriptome-referenced association study of clove shape traits in garlic.

Genome-wide association studies are a powerful approach for identifying genes related to complex traits in organisms, but are limited by the requirement for a reference genome sequence of the species under study. To circumvent this problem, we propose a transcriptome-referenced association study (TRAS) that utilizes a transcriptome generated by single-molecule long-read sequencing as a reference sequence to score population variation at both transcript sequence and expression levels. Candidate transcripts are identified when both scores are associated with a trait and their potential interactions are ascertained by expression quantitative trait loci analysis. Applying this method to characterize garlic clove shape traits in 102 landraces, we identified 22 candidate transcripts, most of which showed extensive interactions. Eight transcripts were long non-coding RNAs (lncRNAs), and the others were proteins involved mainly in carbohydrate metabolism, protein degradation, etc. TRAS, as an efficient tool for association study independent of a reference genome, extends the applicability of association studies to a broad range of species.

Effects of enzyme supplementation on the nutrient, amino acid, and energy utilization efficiency of citrus pulp and hawthorn pulp in Linwu ducks.

The objective of this study was to evaluate the effects of enzyme supplementation on the nutrient, amino acid, and energy utilization efficiency of citrus pulp and hawthorn pulp as unusual feedstuffs in Linwu ducks. Forty ducks were assigned to each treatment group and fed diets with or without complex enzyme supplementation. All birds received the same quantity of raw material (60 g) via the force-feeding procedure. With the exception of leucine and phenylalanine, amino acid concentrations in hawthorn pulp were twice those in citrus pulp. Enzyme supplementation significantly increased apparent dry matter digestibility (ADM) of citrus pulp (P < 0.05), but had no significant effects (P > 0.05) on the apparent and true utilization rates of other nutrients, apparent metabolizable energy (AME), or true metabolizable energy (TME), from citrus pulp and hawthorn pulp by Linwu ducks. However, enzyme supplementation significantly increased (P < 0.05) apparent gross energy, true gross energy, AME, and TME of hawthorn pulp for Linwu ducks. There were no differences in the apparent and true utilization rates of amino acids from citrus pulp (P > 0.56) between the groups, with the exception of arginine (P < 0.05). There was an increasing trend in the apparent and true utilization rates of alanine (P = 0.06) and tyrosine (P = 0.074) from citrus pulp with enzyme supplementation. The apparent and true utilization rates of threonine in hawthorn pulp were increased significantly (P < 0.05) following enzyme supplementation. The addition of exogenous enzymes improved the forage quality of citrus pulp and hawthorn pulp, which represent potential feed resources for husbandry production.

Effect of a microbial phytase on growth performance, plasma parameters and apparent ileal amino acid digestibility in Youxian Sheldrake fed a low-phosphorus corn-soybean diet.

OBJECTIVE: This study investigated the effect of microbial phytase supplementation on growth performance, tibia ash, plasma parameters, apparent ileal digestibility (AID) of amino acid (AA) and apparent digestibility of nutrients in Youxian Sheldrakes fed with low-phosphorus (P) corn-soybean diets. METHODS: A total of 350 Youxian Sheldrakes (7d old) were randomly divided into 5 treatment groups: positive control (PC) group has adequate available P diet (0.42% and 0.38%, starter and grower), negative control (NC) group were deficient in available P (0.32% and 0.28%, starter and grower) and NC diet was supplemented with 3 levels of microbial phytase (500, 750, and 1,000 U/kg). RESULTS: Dietary supplementation of phytase in NC diet improved the average daily gain, increased the levels of serum calcium (Ca), tibia Ca and P, AID of AA and apparent digestibility of energy and Ca in starter stage (p<0.05). There was an increased (p<0.001) in the utilization of P from 17.3% to 23.9%. Phytase supplementation (1,000 U/kg) has shown that the AID of His, Thr, Val, indispensable AA, Glu, Pro, and dispensable AA was higher (p<0.05) than that of NC. Moreover, phytase supplementation improved (p<0.05) serum and tibia Ca and P, AID of AA and apparent digestibility of dry matter, crude protein, energy, P and Ca, and reduced (p<0.05) feed to gain ratio (F/G) and the levels of serum alkaline phosphatase in grower stage. Likewise, an increase (p<0.001) in the utilization of P was noticed from 12.6% to 17.2%. Supplement phytase at 750 U/kg improved the AID of His, Thr, Asp, Cys, Pro, and Ser (p<0.05). CONCLUSION: The microbial phytase supplement could improve growth performance, AID of some AA and apparent utilization of other nutrients in Youxian Sheldrakes, and reduce excreta P load to environment.

Magnolol additive as a replacer of antibiotic enhances the growth performance of Linwu ducks.

Magnolol rich in Magnolia officinalis is a bioactive polyphenolic compound. The aim of this study was to examine the effects of magnolol additive (MA) on growth performance, expression levels of antioxidant-related genes, and intestinal mucosal morphology of Linwu ducks aged from 49 to 70 days, comparing with that of an antibiotic additive (colistin sulfate [CS]). A total of 275, 49-day-old ducks were assigned to 5 groups with 5 cages of 11 ducks each and fed diets supplemented with 0, 100, 200 and 300 mg of MA/kg and 300 mg of CS/kg for 3 weeks, respectively. The results showed that the average daily body weight gain (ADG) was increased significantly in MA-fed groups (200 and 300 mg/kg), compared with the basal diet (BD) group (P < 0.05). The mRNA levels of superoxide dismutase-1 (SOD1), manganese superoxide dismutase-2 (MnSOD2) and catalase (CAT) were also increased significantly in MA groups (P < 0.05). In addition, hematoxylin and eosin staining revealed that Linwu ducks fed the diets with MA had more intact intestinal mucosa than those fed the BD and CS diets. In addition, ileal villus height, ileal villus height/crypt depth ratio (V/C) and duodenal V/C were also improved significantly (P < 0.05). Taken together, these data demonstrated that MA is an effective feed additive to enhance the growth performance of the Linwu ducks by improving the antioxidant and intestinal mucosal status, suggesting that MA will be a potential additive to replace antibiotic (CS).

Identification of an NAC Transcription Factor Family by Deep Transcriptome Sequencing in Onion (Allium cepa L.).

Although onion has been used extensively in the past for cytogenetic studies, molecular analysis has been lacking because the availability of genetic resources is limited. NAM, ATAF, and CUC (NAC) transcription factors (TFs) are plant-specific proteins, and they play key roles in plant growth, development, and stress tolerance. However, none of the onion NAC (CepNAC) genes had been identified thus far. In this study, the transcriptome of onion leaves was analyzed by Illumina paired-end sequencing. Approximately 102.9 million clean sequence reads were produced and used for de novo assembly, which generated 117,189 non-redundant transcripts. Of these transcripts, 39,472 were annotated for their function. In order to mine the CepNAC TFs, CepNAC genes were searched from the transcripts assembled, resulting in the identification of all 39 CepNAC genes. These 39 CepNAC proteins were subjected to phylogenetic analysis together with 47 NAC proteins of known function that were previously identified in other species. The results showed that they can be divided into five groups (NAC-I-V). Interestingly, the NAC-IV and -V groups were found to be likely related to the processes of secondary wall synthesis and stress response, respectively. The transcriptome analysis generated a substantial amount of transcripts, which will aid immensely in identifying important genes and accelerating our understanding of onion growth and development. Moreover, the discovery of 39 CepNAC TFs and the identification of the sequence conservation between them and NAC proteins published will provide a basis for further characterization and validation of their functions in the future.

Chromium improves protein deposition through regulating the mRNA levels of IGF-1, IGF-1R, and Ub in rat skeletal muscle cells.

The aim of this study was to evaluate the impact of three different chromium forms--chromic chloride (CrCl3), chromium picolinate (CrPic), and a newly synthesized complex of chromium chelated with small peptides (CrSP)--on protein metabolism in vitro. In cultured skeletal muscle cells, CrSP was able to increase the basal and insulin-stimulated levels of protein deposition in skeletal muscles cells. CrCl3 and CrPic augmented insulin-stimulated protein synthesis. At the molecular level, insulin significantly increased the mRNA levels of insulin-like growth factor 1 and insulin-like growth factor 1 receptor. These impacts could be enhanced by the addition of chromium, especially CrSP. The mRNA levels of ubiquitin were significantly reduced when cells were cultured with chromium or/and insulin. Assuming that the mRNA level increase or decrease results in increased or decreased levels of these proteins, chromium would improve protein anabolism and reduce protein catabolism and then prove protein deposition in rat skeletal muscle cells.