Genetic Variation of the Ghrelin Signalling System in Individuals with Amphetamine Dependence

The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL) as well as GHS-R1A (GHSR) genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs) and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104) and controls from the general population (n = 310). A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI) composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (p_c = 0.02). A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (p_c = 0.03). The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.     

Dietary metabolizable energy,digestible lysine,available phosphorus levels and exogenous enzymes affect broiler chicken performance

The nutritional composition of diets and the provision of exogenous enzymes play important roles in animal performance. Here, we evaluated the individual and combined impact of nutrients (metabolizable energy (ME), digestible lysine (dLys), available phosphorus and calcium (avP–Ca)) and exogenous multicarbohydrase and phytase complex (MCPC) enyzmes on the growth performance and feed efficiency of broiler chickens from 10 to 42 days (d) of age. Experimental diets were formulated in a Box-Behnken design to contain various levels of ME (11.89, 12.21, 12.54 or 13.06 MJ/kg), dLys (0.91%, 0.93%, 0.96% or 1.00%) and avP/Ca (0.12/0.47%, 0.21/0.58% or 0.33/0.68%). The effect of MCPC was expressed in terms of the extra nutrients released. The diets were formulated to have consistent substrate contents (i.e., arabinoxylan and phytate). Feed intake (FI), BW gain (BWG) and feed conversion ratio (FCR) were described via polynomial equations (R² = 0.99, 0.98 and 0.81, respectively), with interconnections between variables (ME, dLys and avP–Ca). Available P–Ca was the most important factor affecting FI (quadratically), and BWG and FCR (linearly). Reducing the avP content from 0.33% to 0.12% in diets lacking MCPC resulted in 25% and 33% decreases in FI and BWG, respectively, and a 12% increase in FCR. The ME and dLys contents also linearly affected these performance parameters to a lesser degree; FI decreased by 400 g when the ME was reduced by 1.17 MJ/kg, and by 300 g following a 0.09% reduction of dLys, while the same reductions in ME and dLys decreased BWG by 120 g and 150 g, respectively. The inclusion of MCPC alleviated the reduction of FI, BWG and FCR by decreasing the avP–Ca. Thus, ME and dLys were the most important factors affecting BWG and FCR in broilers fed diets containing MCPC. When MCPC was added, ME negatively affected FI (r = −0.89, P < 0.001), whereas the dLys content was correlated with BWG (r = 0.74, P < 0.001). Both ME and dLys affected FCR (r = −0.83 and −0.85, respectively). Supplementing MCPC allowed the reduction of ME, dLys and avP–Ca in the diet without affecting performance. Indeed, MCPC’s effect promoted with the release of the following nutrients: 0.56 MJ ME/kg, 0.06% dLys, and 0.15% and 0.13% avP and Ca, respectively. The results indicate nutrient effect and interaction on performance and feed additive potential for nutrient release.     

Interaction and imbalance between indispensable amino acids in young piglets

Lowering protein level in diets for piglets urge to have knowledge on the piglet’s requirements for essential amino acids (AA) and their interactions. The present studies aimed to determine the interaction between the dietary level of valine (Val) and tryptophan (Trp) and the effect of AA imbalance at two levels of dietary Val on the growth performance of post-weaning piglets. In Experiment 1 (duration 4 weeks), the effects of supplementation of free l-Val (1.0 g/kg) and/or l-Trp (0.5 g/kg) in a low-CP diet (CP 17.7%), marginal in Trp and Val, was studied in a 2×2 factorial design and using an additional reference treatment (CP 19.5%). In Experiment 2 (duration 5 weeks), the influence of a stepwise increase in excess supply of isoleucine (Ile), histidine (His) and leucine (Leu), up to 10, 10% and 30% relative to their requirement values respectively, was evaluated at 60% or 70% standardized ileal digestible (SID) Val relative to SID lysine, using a 3×2 factorial design. In Experiment 1, over the whole experimental period, feed intake (FI) was affected by dietary Trp level (P<0.05) and feed conversion ratio (FCR) by both the level of Trp and Val in the diet (both P<0.05). Increasing Trp level increased FI and decreased FCR while increasing dietary Val level reduced FI and increased FCR. For BW gain (BWG), there was an interaction between dietary level of Trp and Val (P<0.05). Valine supplementation decreased BWG using a diet marginal in Trp, whereas it increased BWG when using a Trp sufficient diet. Piglets fed the low-CP diet with adequate levels of Val and Trp showed at least same performance compared to piglets fed the high CP reference diet. In Experiment 2, increasing dietary Val improved FI and BWG (P<0.001) and tended to improve FCR. Dietary AA excess for Ile, His and Leu reduced FI and BWG (P<0.05) and only affected FCR (P<0.01) in the 1^st week of the study. Dietary level of Val and AA excess did not show interactive effects, except for FCR over the final 2 weeks of the study (P<0.05). In conclusion, an interaction exists between dietary supply of Val and Trp on the zootechnical performance of post-weaning piglets and dietary AA excess for Ile, Leu and His, reduces growth performance of piglets in low-protein diets, independent of the dietary level of Val.     

Effect of different levels of rapeseed meal and sunflower meal and enzyme combination on the performance,digesta viscosity and carcass traits of broiler chickens fed wheat-based diets

The aim of the present experiment was to examine the effect of different levels of rapeseed meal (RSM) and sunflower meal (SFM) and enzyme combination (endoxylanase and β-glucanase) on the production performance, carcass quality, gizzard development and digesta viscosity of broiler chickens. The experimental design was a 3×2 factorial arrangement of treatments evaluating three diet types containing different levels of RSM and SFM (low (L), medium (M) and high (H)) and two levels of enzyme inclusion (0 or 100 g/tonne diet to provide 1220 U xylanase and 152 U β-glucanase per kg diet). Broiler starter and grower/finisher diets were formulated, based on wheat and soya bean meal and containing 50, 50 and 80 g/kg RSM and 0, 50 and 60 g/kg SFM for L, M and H treatments, respectively, during starter period and 80, 80 and 120 g/kg RSM and 0, 80 and 100 g/kg SFM for L, M and H, respectively, during grower/finisher period, and each diet was fed ad libitum to eight pens of 20 male broilers each. During the starter period (1 to 21 days), birds fed the H treatment had lower (P<0.05) BW gain (BWG) compared with those fed the L and M treatments. Diet type also influenced (P<0.05) feed intake (FI). Feeding the H treatment reduced (P<0.05) FI compared with the M treatment. Diet type and enzyme supplementation had no effect (P>0.05) on feed conversion ratio (FCR). During the grower/finisher phase (22 to 42 day) and over the entire period (1 to 42 day) birds fed the H treatment had lower (P<0.05) BWG and higher (P<0.05) FCR compared with those fed the L and M diets. Enzyme supplementation improved (P<0.05) FCR compared with the unsupplemented diets. No interactions (P>0.05) between RSM and SFM inclusion level and enzyme supplementation were observed for any of the measured parameters at any period. Diet type and enzyme supplementation had no effect (P>0.05) on carcass traits, abdominal fat pad, breast meat yield and jejunal digesta viscosity. Diet type influenced (P=0.05) relative empty gizzard weight, where the H treatment had higher relative empty gizzard weight compared with the L treatment. Enzyme supplementation tended (P=0.10) to increase relative empty gizzard weight. The present data suggest that high inclusion of SFM and RSM negatively influenced broiler performance. Enzyme supplementation improved FCR at all levels of RSM and SFM included in this study, but did not recover the reduction in weight gain caused by high inclusion of RSM and SFM.     

Eucalyptus leaves powder,antibiotic and probiotic addition to broiler diets: effect on growth performance,immune response,blood components and carcass traits

The study was conducted to investigate the effects of different levels of eucalyptus powder (EP), virginiamycin and probiotic on performance, immunity, blood components and carcass traits of broiler chickens. A total of 250, 1-day-old male broiler chickens (Ross 308) were randomly allocated to five treatments with five replicates and 10 chicks each, as a completely randomized design. The dietary treatments consisted of: basal diet (BD), BD+0.25% EP, BD+0.5% EP, BD+0.01% of diet probiotic (Protexin), BD+0.02% of diet antibiotic (virginiamycin). Dietary supplementation did not affect feed intake, BW gain (BWG) and feed conversion ratio (FCR) during starter and grower phases, but BWG and FCR were affected during the finisher and whole periods (P<0.05).The highest BWG and lowest FCR were obtained in birds fed with virginiamycin and 0.5% EP. Dietary supplementation significantly increased the relative weight of carcass and breast (P<0.05). Treatments had no effect on relative weights of internal organs and small intestine except for bursa that increased by treatments. Relative length of jejunum also increased by treatments (P<0.05). Antibody production against sheep red blood cells did not changed in primary titer (day 35), but it significantly increased in secondary titer (day 42) by 0.5% EP. White blood cell counts were increased and cholesterol decreased by dietary supplementation (P<0.05). In conclusion, the results of this study showed that 0.5% EP served as a useful replacement for antibiotic and would improve performance and immune response of broiler chickens.     

Association of the apolipoprotein M gene polymorphisms and serum lipid levels

The association of rs707921 and rs707922 SNPs in the apolipoprotein M (APOM) gene and serum lipid levels is still controversial. This study aimed to detect the association of the APOM rs707921 and rs707922 SNPs and several environmental factors with serum lipid profiles. Genotyping of rs707921 and rs707922 was performed in 703 of Mulao’s and 707 of Han’s participants. The serum levels of TG in Mulao, and TG and HDL-C in Han were different between the A and C allele carriers of rs707921 (P < 0.05–0.01); while the serum levels of TG in both Mulao and Han were different between the T and G allele carriers of rs707922 (P < 0.05–0.01). According to the gender-subgroup analysis, the levels of TC in Mulao females, TG and ApoB in Han males, and HDL-C in Han females were associated with the genotypes of rs707921 (P < 0.05 for each); whereas the levels of TG in Mulao males, and TG and ApoB in Han males were correlated with the genotypes of rs707922 (P < 0.05 for each). Serum lipid parameters were also associated with several environmental factors (P < 0.05–0.001). The APOM gene rs707921 and rs707922 SNPs are associated with some serum lipid parameters in the two ethnic groups, but the trends of association suggest that the two SNPs might have racial/ethnic- and/or gender- specificity.     

Association of two variants in the interleukin-6 receptor gene and premature coronary heart disease in a Chinese Han population

Two novel single nucleotide polymorphisms (SNPs; rs7529229 and rs2228145) in the interleukin-6 receptor (IL6R) gene have recently been associated with coronary heart disease (CHD) in a European population. We sought to replicate this finding and to investigate associations of these two SNPs with the severity and clinical phenotypes of premature CHD in a Chinese Han population. A total of 418 patients were studied, including 187 cases with coronary stenosis ≥50 % or acute myocardial infarction (males < 55 years and females < 65 years) and 231 controls without documented CHD. A ligase detection reaction was performed to detect rs7529229 and rs2228145. There were no differences between the controls and premature CHD groups in the frequencies for the three genotypes and alleles of rs7529229 and rs2228145 (all P > 0.05), nor did they differ between the two groups when grouped by gender (all P > 0.05). There were also no associations between these two SNPs and the severity of coronary lesions or clinical phenotypes of premature CHD (all P > 0.05). Our results do not support an association between rs7529229 or rs2228145 with premature CHD in the Chinese Han population. Further studies are warranted to elucidate the role of these two SNPs in the development of atherosclerosis and CHD.     

Associations of polymorphism within the GHSR gene with growth traits in Nanyang cattle

GH secretagogue receptor (ghrelin receptor, GHSR) is known to be involved in the control of GH release by mediating the strong stimulatory effect of the endogenous ligand, ghrelin, on GH secretion. Associations between the GHSR gene polymorphism and the growth traits were revealed in Nanyang cattle. The mutations at nt456(G > A) and nt667(C > T) were complete linkage and located in exon 1 of the coding region of the GHSR gene. Least squares analysis revealed a significant statistical effect (P < 0.05) of the GHSR gene different genotypes on body weight and average daily gain at 6 months of age in Nanyang cattle. Individuals with GHSR-MM genotype showed higher body weight and average daily gain than individuals with GHSR-MN genotype.     

Genome-wide association study of body weight in Wenshang Barred chicken based on the SLAF-seq technology

Chicken body weight (BW) is an economically important trait, and many studies have been conducted on genetic selection for BW. However, previous studies have detected functional chromosome mutations or regions using gene chips. The present study used the specific-locus amplified fragment sequencing (SLAF-seq) technology to perform a genome-wide association study (GWAS) on purebred Wengshang Barred chicken. A total of 1,286,715 single-nucleotide polymorphisms (SNPs) were detected, and 175,211 SNPs were selected as candidate SNPs for genome-wide association analysis using TASSEL general linear models. Six SNP markers reached genome-wide significance. Of these, rs732048524, rs735522839, rs738991545, and rs15837818 were significantly associated with body weight at 28 days (BW28), while rs314086457 and rs315694878 were significantly associated with BW120. These SNPs are close to seven genes (PRSS23, ME3, FAM181B, NABP1, SDPR, TSSK6L2, and RBBP8). Moreover, 24 BW-associated SNPs reached “suggestive” genome-wide significance. Of these, 6, 13, 1, and 4 SNPs were associated with BW28, BW56, BW80, and BW120, respectively. These results would enrich the studies on BW and promote the use of Chinese chicken, especially the Wenshang Barred chicken.     

Effects of low to moderate levels of deoxynivalenol on feed and water intake,weight gain,and slaughtering traits of broiler chickens

The aim of the study was to evaluate the effects of low to moderate oral exposure to the Fusarium toxin deoxynivalenol (DON; derived from culture material) on performance, water intake, and carcass parameters of broilers during early and late developmental phases. A total of 160 Ross 308 broilers were randomly allocated to four different feeding groups (n = 40/group) including 0 (control), 2.5, 5, and 10 mg DON/kg wheat-soybean meal-based feed. Three consecutive replicates of the experiment were performed. Half of the broilers were slaughtered in week 3 of the trial whereas the other half were slaughtered in week 5. Dry matter intake (DMI) and water intake (WI) were recorded on a daily basis and the body weight (BW) and BW gain (BWG) were determined weekly. The following carcass traits were recorded and calculated in absolute and relative data: dressed carcass weight, breast muscle weight, leg weight, and liver weight. Data showed that BW (P < 0.001), BWG (P = 0.005), and DMI (P < 0.001) were reduced by DON-feeding during the entire feeding period. The ratio of DMI to body weight gain (DMI/BWG) was not affected by the treatment. However, the ratio of water to DMI (WI/DMI) increased in DON-treated birds (P = 0.021). Contrast analysis showed that DON tendentially reduced slaughter weight (P = 0.082) and decreased leg yield (P = 0.037) in DON-fed chickens in week 5 of the experiment. Liver organ weight decreased in the 3-week-old DON-fed broilers compared to that in the control-fed birds (P = 0.037). In conclusion, the study suggests that DMI and BW were negatively affected under the experimental conditions at DON levels lower than the current guidance value in the European Union of 5 mg/kg feed. The study also indicates that broilers fed on low to moderate level DON-contaminated diets showed increased WI/DMI ratio which might have negative influence on wet litter syndrome.     

Interaction between obesity-related genes, FTO and MC4R, associated to an increase of breast cancer risk

Breast cancer (BC) is a complex disease and obesity is a well-known risk factor for its development, especially after menopause. Several studies have shown Single Nucleotide Polymorphisms (SNPs) linked to overweight and obesity, such as: rs1121980 (T/C) and rs9939609 (A/T) in Fat Mass and Obesity Associated gene (FTO) and rs17782313 (T/C) in Melanocortin 4 Receptor gene (MC4R). Thus, we aimed to investigate the association between these obesity-related SNPs and BC risk. One hundred BC patients and 148 healthy women from Santa Catarina, Brazil entered the study. SNPs were genotyped using Taqman assays. For statistical analyses SNPStats and SPSS softwares were used. Association analyses were performed by logistic regression and were adjusted for age and Body mass index (BMI). Multiple SNPs inheritance models (log-additive, dominant, recessive, codominant) were performed to determine odds ratios (ORs), assuming 95 % confidence interval (CI) and P value = 0.05 as the significance limit. When analyzed alone, FTO rs1121980 and rs9939609 did not show significant associations with BC development, however MC4R rs17782313 showed increased risk for BC even after adjustments (P-value = 0.032). Interestingly, the interaction of FTO and MC4R polymorphisms showed a powerful association with BC. We observed a 4.59-fold increased risk for woman who have the allele combination C/T/C (FTO rs1121980/FTO rs9939609/MC4R rs17782313) (P-value = 0.0011, adjusted for age and BMI). We found important and unpublished associations between these obesity-related genes and BC risk. These associations seem to be independent of their effect on BMI, indicating a direct role of the interaction between FTO and MC4R polymorphisms in BC development.     

The association of apolipoprotein E gene polymorphisms with cerebral palsy in Chinese infants

Apolipoprotein E (APOE, protein; ApoE, gene) is a lipid transport protein abundantly present in brain cells. Previous studies have suggested that there is an association between genetic variants of ApoE and susceptibility to cerebral palsy (CP). The purpose of this study was to explore whether the ApoE gene is involved in the etiology of CP in the Chinese population. In this study, 350 CP patients and 242 healthy control children were recruited. Genomic DNA was prepared from venous blood and all five single nucleotide polymorphisms (SNPs) in ApoE (rs769446, rs405509, rs121918399, rs429358, and rs190853081) were detected by the MassARRAY platform-based genotyping approach. The SHEsis program was used to analyze the genotyping data, and we systemically analyzed the association of the ApoE SNPs with different subtypes of CP. No significant association was detected between the e4 identified by the C allele of rs429358 and CP, but there were significant differences in allelic frequencies between the CP patients and controls at rs769446 (P = 0.005, P = 0.025 after Bonferroni correction), as well as between the CP patients with preterm birth (<34 gestational weeks) and controls at rs769446 (P = 0.001, P = 0.005 after Bonferroni correction). A haplotype consisting of the five SNPs rs769446(C), rs405509(C), rs121918399(C), rs429358(T), and rs190853081(G) was associated with a decreased risk of CP (P = 0.002 after Bonferroni correction). However, we found no significant association between any of the other three SNPs and CP based on different subgroup analyses. This study provides the first evidence that ApoE gene polymorphisms are a potential risk factor for CP in the Chinese population.     

Genome-wide scan revealed that polymorphisms in the PNPLA3, SAMM50, and PARVB genes are associated with development and progression of nonalcoholic fatty liver disease in Japan

We examined the genetic background of nonalcoholic fatty liver disease (NAFLD) in the Japanese population, by performing a genome-wide association study (GWAS). For GWAS, 392 Japanese NAFLD subjects and 934 control individuals were analyzed. For replication studies, 172 NAFLD and 1,012 control subjects were monitored. After quality control, 261,540 single-nucleotide polymorphisms (SNPs) in autosomal chromosomes were analyzed using a trend test. Association analysis was also performed using multiple logistic regression analysis using genotypes, age, gender and body mass index (BMI) as independent variables. Multiple linear regression analyses were performed to evaluate allelic effect of significant SNPs on biochemical traits and histological parameters adjusted by age, gender, and BMI. Rs738409 in the PNPLA3 gene was most strongly associated with NAFLD after adjustment (P = 6.8 × 10^?14, OR = 2.05). Rs2896019, and rs381062 in the PNPLA3 gene, rs738491, rs3761472, and rs2143571 in the SAMM50 gene, rs6006473, rs5764455, and rs6006611 in the PARVB gene had also significant P values (<2.0 × 10^?10) and high odds ratios (1.84–2.02). These SNPs were found to be in the same linkage disequilibrium block and were associated with decreased serum triglycerides and increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in NAFLD patients. These SNPs were associated with steatosis grade and NAFLD activity score (NAS). Rs738409, rs2896019, rs738491, rs6006473, rs5764455, and rs6006611 were associated with fibrosis. Polymorphisms in the SAMM50 and PARVB genes in addition to those in the PNPLA3 gene were observed to be associated with the development and progression of NAFLD.     

Effects of dietary chromium picolinate and peppermint essential oil on growth performance and blood biochemical parameters of broiler chicks reared under heat stress conditions

A study was conducted using 240 female day-old broiler chicks to evaluate the effects of dietary chromium picolinate (CrPic), peppermint essential oil (P.mint), or their combination on growth performance and blood biochemical parameters of female broiler chicks raised under heat stress conditions (HS, 23.9 to 38 °C cycling). Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were obtained from 1 to 42 days of age. Furthermore, at the end of the experiment (day 42), birds were bled to determine some blood biochemical parameters and weighed for final body weight (BW). ADFI, ADG, and BW were not influenced significantly by dietary CrPic and P.mint (P?>?0.05). A significant interaction between dietary CrPic and P.mint on FCR (P?=?0.012) was detected. FCR significantly decreased in chicks fed the diet including both CrPic and P.mint compared with the CrPic group. Significant interaction between dietary P.mint and CrPic on serum concentrations of triglycerides, glucose, and albumin were observed (P?<?0.05), but the other measured blood biochemical parameters were not statistically affected by dietary treatments (P?>?0.05). The serum concentrations of glucose, triglycerides were decreased (P?<?0.05) in broilers fed the diet including both CrPic and P.mint. Plasma chromium (Cr) content increased significantly (P?<?0.05) in birds fed the CrPic-included diet compared with the control group (P?<?0.05). From the results of the present experiment it can be concluded that dietary supplementation with combined P.mint and CrPic could have beneficial effects on some blood biochemical parameters of female chicks reared under heat stress conditions.     

Preliminary findings on the influence of FTO rs9939609 and MC4R rs17782313 polymorphisms on resting energy expenditure,leptin and thyrotropin levels in obese non-morbid premenopausal women

Given that leptin, ghrelin and thyrotropin play a major role in the regulation of resting energy expenditure (REE) and that the FTO rs9939609 and the MC4R rs17782313 polymorphisms have been proposed to affect energy homeostasis, we hypothesized that both polymorphisms are associated with REE and that these relationships can be mediated by leptin, ghrelin and thyrotropin in obesity. Therefore, the present study aimed to examine the relationships between FTO rs9939609 and the MC4R rs17782313 with REE, leptin, ghrelin and thyrotropin levels in obese women. The study comprised 77 obese (body mass index 34.0?±?2.8 kg/m²) women (age 36.7?±?7 years). We measured body composition by dual-energy X-ray absorptiometry and REE by indirect calorimetry. We analysed fasting leptin, ghrelin and thyrotropin levels and the ratio of leptin to fat mass was calculated. Genotype distributions of the polymorphisms did not deviate from Hardy–Weinberg expectations (P values >0.2). Women carrying the A allele of the FTO rs9939609 had lower REE (1,580?±?22 vs. 1,739?±?35 kcal/day, P?<?0.001) and higher leptin to fat mass ratio (1.33?±?0.05 vs. 1.13?±?0.08 ng/ml kg, P?<?0.05) and thyrotropin levels (1.93?±?0.10 vs. 1.53?±?0.16 μU/ml, P?<?0.05) regardless of age and body mass index. We found no significant influence of the MC4R rs17782313 on energy metabolism or biochemical variables. Our findings confirm that the A allele of the FTO rs9939609 is associated with lower REE and increased plasma leptin levels. We also found an association between the FTO rs9939609 and thyrotropin, suggesting the possible influence of FTO in the hypothalamic–pituitary–thyroid axis as a potential mechanism of the increased adiposity.     

Effect of l-theanine on the growth performance,immune function,and jejunum morphology and antioxidant status of ducks

l-theanine is a unique nonproteinogenic amino acid found in tea, and has recently received considerable attention because of its various biological activities. However, there is no available research report on the use of l-theanine as a feed additive in ducks. This study was conducted to investigate the potential benefits and appropriate dosages of l-theanine on the growth performance, immune function, serum biochemical parameters, and jejunum morphology and antioxidant capacity of ducks. A total of 600 1-day-old Chaohu ducks were randomly allocated into five dietary treatment groups supplemented with 0 (control group), 300, 600, 900 and 1500 mg/kg of l-theanine. Each group included five replicates of 24 birds each. Body weight at day 28 was increased (P<0.05) by l-theanine. From days 15 to 28, l-theanine elevated cumulative BW gain (BWG) and cumulative feed intake (FI), and decreased feed to gain ratio. From days 1 to 28, l-theanine elevated (P<0.05) cumulative BWG and cumulative FI. l-theanine elevated (P<0.05) the relative weight of bursa of Fabricus (day 14), thymus (day 14), spleen (day 28) and liver (day 28). On day 28, l-theanine decreased (P<0.05) serum glucose, uric acid, triacylglycerol, total cholesterol, low-density lipoprotein cholesterol, insulin, interleukin-2 (IL-2) and IL-6 contents, and elevated (P<0.05) serum total protein, globulin (GLB), immune globulin A (IgA) and IgG contents, but only serum insulin, interferon-γ, tumor necrosis factor-α and IL-6 contents was decreased (P<0.05) and serum GLB and IgM content was elevated (P<0.05) by l-theanine on day 14. On day 14, l-theanine decreased (P<0.05) jejunum crypt depth, and elevated (P<0.05) jejunum villus height, villus height to crypt depth ratio (V/C), goblet cell number and total superoxide dismutase (T-SOD) activity. On day 28, l-theanine decreased (P<0.05) jejunum malondialdehyde content, and elevated (P<0.05) jejunum villus height, V/C, goblet cell number, and T-SOD, catalase and glutathione peroxidase activities. l-theanine levels caused quadratic effect on the growth performance, relative organ weight, serum parameters, jejunum morphology and antioxidant capacity. In conclusion, l-theanine can be used as a promising feed additive for ducks, and its optimal supplementation level was 600 to 900 mg/kg based on the current experimental condition.     

The IGF1 pathway genes and their association with age of puberty in cattle

Insulin‐like growth factor I (somatomedin C) (IGF1) influences gonadotrophin‐releasing hormone (GnRH) neurons during puberty, and GnRH release guides pubertal development. Therefore, genes of the IGF1 pathway are biological candidates for the identification of single‐nucleotide polymorphisms (SNPs) affecting age of puberty. In a genome‐wide association study, genotyped heifers were Tropical Composite (TCOMP, n = 866) or Brahman (BRAH, n = 843), with observation of age at first corpus luteum defining puberty. We examined SNPs in or near genes of the IGF1 pathway and report seven genes associated with age at puberty in cattle: IGF1R, IGFBP2, IGFBP4, PERK (HUGO symbol EIF2AK3), PIK3R1, GSK3B and IRS1. SNPs in the IGF1 receptor (IGF1R) showed the most promising associations: two SNPs were associated with puberty in TCOMP (P < 0.05) and one in BRAH (P = 0.00009). This last SNP explained 2% of the genetic variation (R² = 2.04%) for age of puberty in BRAH. Hence, IGF1R was examined further. Additional SNPs were genotyped, and haplotypes were analysed. To test more SNPs in this gene, four new SNPs from dbSNP were selected and genotyped. Single SNP and haploytpe analysis revealed associations with age of puberty in both breeds. There were two haplotypes of 12 IGF1R SNPs associated with puberty in BRAH (P < 0.05) and one in TCOMP (P < 0.05). One haplotype of two SNPs was associated (P < 0.01) with puberty in BRAH, but not in TCOMP. In conclusion, the IGF1 pathway appeared more relevant for age of puberty in Brahman cattle, and IGF1R showed higher significance when compared with other genes from the pathway.     

Three Novel SNPs in the Coding Region of the Bovine MC3R Gene and Their Associations with Growth Traits

The involvement of melanocortin-3 receptor (MC3R) is well recognized in the regulation of feeding efficiency, body weight, and energy homeostasis. The objective of this study was to investigate the associations between MC3R gene polymorphisms and growth traits. Three novel SNPs (c.24C→T, c.220T→A, c.734G→C) and five haplotypes were identified in 234 Xiangxi cattle. The associations between MC3R gene polymorphisms and growth traits indicated that the individuals with TT and AT genotypes maintained higher body weight than those with the AA genotype at the c.220T→A locus (P < 0.05). The animals with GG and CG genotypes had higher heart girth and body weight than those with the CC genotype at c.734G→C (P < 0.05). The animals with H3H3 and H2H3 haplotype combinations had higher body weight than those with other haplotype combinations (P < 0.05). The results suggest that these SNPs in the MC3R gene might be useful genetic markers for marker-assisted selection and cattle breeding.     

Novel SNPs of the Caprine Growth Hormone Secretagogue Receptor (GHSR) Gene and Their Association with Growth Traits in Goats

Growth hormone secretagogue receptor (GHSR), a G protein-coupled receptor that binds ghrelin, plays an important role in the central regulation of pituitary growth hormone secretion, food intake, and energy homeostasis. This study analyzed polymorphism of the caprine GHSR gene as a genetic marker candidate for growth traits in goats. Two single nucleotide polymorphisms (GU014697:g.165G→A and GU014697:g.548T→C) were identified in exon 2 of the caprine GHSR gene by PCR-single-strand conformation polymorphism and DNA sequencing methods. Their associations with growth traits were analyzed in 313 Xuhuai goats. The results indicated that GU014697:g.548T→C had significant effects on growth traits. Body length and body length index were significantly higher in individuals with genotype TT than CC and CT in (P < 0.05). TT individuals also tended to have better performance in other traits, such as body height and chest circumference, although there were no statistical differences (P > 0.05). This suggests that GHSR is a strong candidate gene that affects growth traits in goats.     

Investigation of four candidate genes (IGF2, JHDM1A, COPB1 and TEF1) for growth rate and backfat thickness traits on SSC2q in Large White pigs

As important quantitative traits, the growth rate and backfat thickness are controlled by multiple genes. The aim of this investigation was to evaluate the effect of the single and multiple SNPs of four candidate genes (IGF2, JHDM1A, COPB1 and TEF-1) on growth rate and backfat thickness. The four candidate genes were mapped on the p arm of SSC 2, and there are several QTLs, such as average daily gain, backfat thickness, an imprinted QTLs affecting muscle mass and fat deposition have been reported in this region. The polymorphisms of these genes were detected using PCR–RFLP methods, mixed procedure was used to analyze the single marker association with the growth and backfat thickness traits, and the gene–gene combination was investigated using multiple-markers analysis. The single marker association analysis indicated that the IGF2 intron-3 g.3072G > A and the substitution g.93G > A of TEF-1 gene were significantly associated with the age at 100 kg (P < 0.05). The JHDM1A 3′UTR g.224C > G, the c.3096C > T polymorphism of COPB1 gene and the substitution g.93G > A of TEF-1 gene were all significantly associated with the backfat at the shoulder (P < 0.05), backfat at the last rib, backfat at the lumbar, and the average backfat thickness, respectively. The multiple-markers analysis indicated that IGF2 and TEF-1 integrated gene networks for the age at 100 kg. Therefore, we can suggest that the polymorphism of IGF2 and TEF-1 gene could be used in marker-assisted selection for the age at 100 kg in Large White pigs.