Two plant enzymes, namely actinidin (A) and papain (P), were used to pretreat bovine skin at the respective optimum pH and temperature of the enzymes for 48 h at the level of 0, 5, 10, 15, 20, and 25 unit/g of skin, and gelatin extraction was done at 60°C for 6 h. Gelatin yield from actinidin at level 20 (A20) (22.67%) and papain at level 20 (P20) (23.59%) were significantly (P < 0.05) higher than control (17.90%). The gel strength values for gelatin extracted using actinidin enzyme (GEA) were significantly (P < 0.05) higher than the control (283.35 g), and the gel strength for A20 was 366.39 g. However, gelatin extracted using papain enzyme (GEP) showed relatively lower gel strength. The GEA sample viscosities were significantly (P < 0.05) higher than control (12.10 mPa.s). GEA samples revealed overall degradation of β chains and presence of α chains and lower molecular weight peptides, whereas β and α chains were completely absent and lower molecular weight peptides were seen in all the GEP samples. Fourier-transform infrared (FTIR) spectra indicated a greater loss of molecular order and more disruption in the α helical structure of P20 compared to A20 and control gelatins. Scanning electron microscopy (SEM) revealed interconnected bigger particle size and denser structure with least number of voids in A20 than P20 and control gelatin samples. Thus, it was concluded that actinidin, particularly at level 20 unit/g of skin, could be used to improve the yield and properties of gelatin from bovine skin.

Bovine skin was incubated with plant enzymes bromelain (B) and zingibain (Z) at the level of 0, 5, 10, 15, 20 and 25 unit/g of skin and gelatin was extracted at 60 °C for 6 h. Control gelatin was extracted without enzymatic pretreatment. The yield and gel strength were 17.90% and 283.35 g for the control samples and 22.26% and 160.88 g for B20 samples. The zingibain extracted gelatin (GEZ) samples failed to form gel. Viscosities of GEZ gelatins were significantly (P \ 0.05) lower than the gelatins extracted using bromelain (GEB). b and a chains were absolutely degraded in all GEB and GEZ samples. Only smear bands were observed in GEZ gelatins whereas GEB samples revealed presence of low molecular weight polypeptides. Loss of molecular order was noticed in Z5 as elaborated by Fourier transform infrared (FTIR) spectroscopy. Larger particle size, denser and inter-connected irregular network was observed in B20 under scanning electron microscopy. Based on the results obtained, bromelain, particularly at level 20, could be used to obtain a better quality gelatin with higher yield compared to zingibain.

This study aimed to determine influence of corn inclusion on glutathion peroxidase (GPx) activity, selected minerals concentration, and gene expression in sheep-fed palm kernel cake (PKC) and urea-treated rice straw. Twenty-seven of Dorper sheep were divided into three groups and fed a basal diet of (20% rice straw and 80% concentrate) with addition of ground corn at either 0% (T1), 5% (T2), or 10% (T3), respectively. After 120 days feeding trial, all animals were slaughtered and tissue samples of kidney, liver, and muscles were taken for enzyme and mineral analyses. The results showed that Cu concentration in the liver was lower treatment T3 compared to the control and T2. The serum activity of GPx was higher in T2 than in T3 at day 120 of experiment. Serum malondialdehyde (MDA) concentrations decreased at day 80 in sheep on T3, whereas MDA of liver increased linearly with increasing corn supplementation. The qRT-PCR analyses revealed significant up-regulation of ATP7A and MIa genes in T3, while hepatic Cu/Zn SOD, GPx1, and GPx4 mRNA showed a higher expression in lamb hepatocytes in T3 compared to those on T1. Present study results suggest that feeding PKC as basal diet can increase antioxidant activity, but cause liver dysfunction in sheep. Inclusion corn was found to regulate transcriptional levels of the GPx family and metallothionein genes. These genes may play a role in the antioxidant protection response and reduce incidence of toxicity associated with Cu.

The autolysis of pretreated bovine skin (PBS) (treated with 0.1 M NaOH and 1% HCl), its endogenous proteases, inhibitors and their effects on quality attributes of gelatin were examined. PBS was subjected to different temperatures (20-90 °C) and pH (2-9) and treated with different protease inhibitors. Maximum autolytic activity of PBS was observed at 40 °C and pH 5. Ethylene-bis (oxyethylenenitrilo) tetraacetic acid (EGTA) was the most effective in impeding the degradation of γ-, β- and α- chains of PBS protein indicating that metallocollagenases were the predominant endogenous proteases in bovine skin. Gelatin was extracted in the absence (GAE) and presence (GPE) of EGTA, and EGTA with papain enzyme (GPEP). GPEP had a higher yield and lower gel strength than GEA and GPE. Metallocollagenases partook in the degradation of gelatin thereby affecting its functional properties. Pretreating PBS with or without EGTA, and papain influenced the quality attributes of gelatin.

The effects of RPF on metabolites and reproductive genes in testes of Malin ram was investigated. Twenty Malin rams (36.6kg ± 5.57 kg of bodyweight), were subjected to four dietary treatments; A: basal diet without rumen-protected fat (RPF), B; basal diet with 2% prilled fat, C; basal diet with 2% calcium salt and D; basal diet with 2% canola oil. At the end of the experiment four out of five animals from each group were slaughtered. The testes were excised for metabolites and gene expression stud-ies. The genes tested were associated to testes development and spermatogenesis (ODF1, SERPINA10, CatSper4, AdipoR2 and DAZL). Feeding RPF with calcium salt (Treatment C) has resulted in the up-regulation more than two folds in all reproductive genes. There were metabolites changes occurred between the groups and identified 44 important putative metabolites present in the testes. In conclu-sion, feeding of RPF to the animals as a source of energy has up-regulated the genes and identified the metabolites involve in the male reproductive tissues and activities.