Potential angiotensin I converting enzyme inhibitory peptides from gluten hydrolysate: Biochemical characterization and molecular docking study

The present study was carried out to characterize ACE inhibitory peptides which are released from the trypsin hydrolysate of wheat gluten protein. In silico proteolitic digestion of a high molecular weight glutenin subunit was performed. Among the resultant fragments, four peptides were selected for chemical synthesis based on the chemoinformatics studies and docking properties. The ACE inhibitory activity and kinetic parameters of the most important peptides were determined. Molecular docking simulation was also performed to predict the sites on ACE in which these peptides bind and displayed inhibition mechanisms. Two peptide sequences of IPALLKR (P4) and AQQLAAQLPAMCR (P6) showed higher ACE inhibitory activity among peptide collection. The IC₅₀ values of P6 and P4 were 43 ± 1.3 μM and 68 ± 2.8 μM, respectively. P6 peptide was proved to be a more potent ACE inhibitor than P4 peptide. Lineweaver-Burk plots revealed that P6 and P4 behaved as non-competitive and competitive ACE inhibitors, respectively. The simulations showed that P4 bound to the active site region. Conversely, P6 bound to the N-terminus entrance of substrate tunnel and obstructed the substrate access into the catalytic site. Overall, the results showed that these peptides would be considered as a model for discovering new bio-compatible ACE inhibitors.     

Effects of supplemental dietary l‐carnitine and ractopamine on the performance of juvenile rainbow trout,Oncorhynchus mykiss

This study was carried out to investigate a possible protein‐sparing action of l ‐carnitine and ractopamine in rainbow trout, Oncorhynchus mykiss. An 8‐week feeding trial was carried out to evaluate the effects of supplementation of three levels of l ‐carnitine (0, 1 and 2 g kg^?1) and two levels of ractopamine (0 and 10 mg kg^?1) on growth performance, fillet fatty acid compositions and blood biochemical parameters in a 3 × 2 factorial experimental design. Ractopamine and 1 g kg^?1 carnitine improved the specific growth rate (1.03% and 1.05% day^?1), feed conversion ratio (FCR, 1.3 and 1.29), protein efficiency ratio (PER, 1.88 and 1.85) of fish and crude protein (73.5 and 73.8) content of fish fillet. l ‐carnitine and ractopamine increased the levels of albumin, total protein and globulin in the serum of fish. Apart from eicosapentaenoic acid and docosahexaenoic acid, other fatty acids of fish fillet were increased by ractopamine, while total saturated fatty acids were almost intact. However, the total n‐3 poly unsaturated fatty acids were reduced by l ‐carnitine supplementation (P<0.05). The present study showed that 1 g kg^?1l ‐carnitine and 10 mg kg^?1 ractopamine each can improve the performance of rainbow trout and their combination in diet could enhance the protein level and change the fatty acids profile in fillet muscle.     

Effects of electron beam irradiation on dry matter degradation of wheat straw in the rumen

The effect of electron beam irradiation at doses of 100, 200 and 300 kGy on ruminal dry matter degradation kinetics of wheat straw was investigated. Samples were irradiated by electron beam irradiator under identical conditions of temperature and humidity. Nylon bags of untreated or irradiated wheat straw were suspended in the rumen of three Taleshi steers for up to 96 h and resulting data were fitted to non-linear degradation model to calculate degradation parameters of dry matter. Results show that the washout fractions of dry matter increased linearly (p<0.001), but potentially degradable fraction and degradation rate decreased linearly (p<0.001) by electron beam irradiation. As a consequence, the effective degradability of dry matter increased linearly (p<0.001) with increasing irradiation dose. Electron beam irradiation at doses of 100, 200 and 300 kGy increased the effective degradability of dry matter at rumen outflow rate of 0.05/h by about 7, 15 and 18%, respectively. In the condition of this study, electron beam irradiation at dose of 200 kGy appeared to be a suitable dose for improving dry matter degradability of wheat straw in the rumen.     

Ileal MUC2 gene expression and microbial population,but not growth performance and immune response,are influenced by in ovo injection of probiotics in broiler chickens

1. The objective of present study was to evaluate the effects of intra-amniotic injection of different probiotic strains (Bacillus subtilis, Enterococcus faecium and Pediococcus acidilactici) on the intestinal MUC2 gene expression, microbial population, growth performance and immune response in broiler chicken.

2. In a completely randomised design, different probiotic strains were injected into the amniotic fluid of the 480 live embryos (d 18 of incubation), with 4 treatments and 5 replicates. Ileal MUC2 gene expression, microbial profile, growth performance and immune response were determined.

3. Injection of probiotic strains, especially B. subtilis, had significant effect on expression of the MUC2 on d 21 of incubation and d 3 post-hatch, but not on d 19 of incubation.

4. Injection of the probiotic strains decreased significantly the Escherichia coli population and increased the lactic acid bacteria population during the first week post-hatch.

5. Inoculation of probiotics had no significant effect on antibody titres against Newcastle disease virus, antibody titres against sheep red blood cell and cell-mediated immune response of chickens compared to control.

6. In ovo injection of the probiotic strains had no significant effect on growth performance of broiler chickens.

7. It was concluded that injection of probiotic bacteria especially B. subtilis into the amniotic fluid has a beneficial effect on ileal MUC2 gene expression and bacteria population during the first week post-hatch, but has no effect on growth performance and immune response in broiler chickens.     

Effects of different fat sources (saturated and unsaturated) on reproductive performance and biological indices of ewes during flushing period

This study was conducted to evaluate the effect of feeding different sources of fat during flushing period on the reproductive performance, lambing percent, and twin numbers of Afshari ewes. A total of 84 ewes (mean weight 48 ± 3 kg; age: 3–4 years) were divided into seven groups of 12 animals and received flushing-specific rations for 5 weeks. The control group just received a basic ration (non-flushing). Lipid sources were calcium salt of palm oil (CaP), pure palm oil (PO), calcium salt of flaxseed (CaFL), calcium salt of sunflower oil (CaSF), flaxseed oil (FLO), and sunflower oil (SFO). Estrous cycles were synchronized in all ewes using 14-day CIDRs followed by 400-IU PMSG injection at the time of CIDR removal. Fertility and lambing percent were higher in ewes fed with diets containing calcium salts of flaxseed and SFO, as compared to other treatments. Total number of lambs in flushing treatments was significantly higher than that in the control group (p < 0.01). Serum cholesterol and progesterone levels were significantly greater in omega-3 (CaFL) and omega-6 (CaSF) treatments relative to other treatments (p < 0.01). It was concluded that supplementing the flushing diet with calcium salts of fatty acids (CSFA) increased blood metabolites and hormones related to reproductive performance; and improved fertility, lambing rate and ewes of CaFL treatment have the highest number of lambs (16 lambs) between different groups. Using saturated and unsaturated fatty acids, especially in their CSFA forms during flushing period, could improve the reproduction problems induced by progesterone deficiency, lack of durability of the fetus due to hormonal instability, and abortion control factors.     

The effect of multiplex-PCR-assessed major pathogens causing subclinical mastitis on somatic cell profiles

The major pathogens causing mastitis were evaluated by multiplex-polymerase chain reaction (M-PCR) with self-designed primers in four quarters of the first, third, and fifth parities in industrial, semi-industrial, and traditional dairy cattle farms in Iran. With the incidence of infection in the quarters by Staphylococcus aureus and Streptococcus agalactiae, the mean log somatic cell count (log SCC) increased from 5.06 to 5.77. The smallest changes occurred with Escherichia coli. Contagious pathogens, when compared with environmental pathogens, were more prevalent and common and created more profound quantitative and qualitative changes in SCC profiles. The second part of the study surveyed the diversity of contaminating pathogens and their effect on quantitative and qualitative profiles of somatic cells. M-PCR was used to determine the absence (M-PCR(-)) and presence of one (M-PCR(+1)), two (M-PCR(+2)), and three (M-PCR(+3)) major pathogens in raw milk samples. Quarter log SCC increased from 5.06 (for M-PCR(-1)) to 5.5 (for M-PCR(+1)), 5.7 (for M-PCR(+2)), and 6 (for M-PCR(+3)). Percent changes in polymorphonuclears (PMNs) were not significant between different quarters and parities but were significant between different farms in terms of pathogen diversity (P?相似文献