Effects of dietary alfalfa flavonoids on the performance, meat quality and lipid oxidation of growing rabbits.

OBJECTIVE: The present experiment has tested the effect of dietary alfalfa flavonoids (AAF) supplementation on the productive performances, carcass characteristics, meat quality and lipid oxidation of growing rabbits. METHODS: One hundred and sixty crossbred rabbits (42 days old) were divided into four groups of forty animals each and were fed either a control diet (AAF0) or an AAF0 diet supplemented with 400, 800, or 1,200 mg of AAF/kg per diet (AAF4, AAF8, and AAF12, respectively) from weaning to slaughtering (102 days old). Performance data were recorded over a period of 60 days. At the end of the trial, 12 rabbits were slaughtered per group, and the carcass characteristics were recorded. Moreover, the plasma, liver and dorsal muscles were sampled from 12 rabbits/group, and were analyzed for lipid oxidation. RESULTS: No significant differences were recorded for the performance, carcass characteristics and meat quality traits except for lightness parameter that was lower in the control group. Dietary AAF supplementation significantly (p<0.01) affected the malondialdehyde (MDA) levels of the frozen meat in a dose-related manner, with the lowest value (0.24 mg MDA/kg fresh meat) recorded in the AAF12 group samples. CONCLUSION: These findings indicated that the dietary inclusion of AAF in rabbit diets improved muscle oxidation stability with no adverse effects on the growth performance of the animals even if a slight impact on meat lightness color parameter was recorded.

Optimization of Ultrasonic-Assisted Extraction of Flavonoid Compounds and Antioxidants from Alfalfa Using Response Surface Method.

Ultrasonic-assisted extraction (UAE) was used to extract flavonoid-enriched antioxidants from alfalfa aerial part. Response surface methodology (RSM), based on a four-factor, five-level central composite design (CCD), was employed to obtain the optimal extraction parameters, in which the flavonoid content was maximum and the antioxidant activity of the extracts was strongest. Radical scavenging capacity of the extracts, which represents the amounts of antioxidants in alfalfa, was determined by using 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods. The results showed good fit with the proposed models for the total flavonoid extraction (R² = 0.9849), for the antioxidant extraction assayed by ABTS method (R² = 0.9764), and by DPPH method (R² = 0.9806). Optimized extraction conditions for total flavonoids was a ratio of liquid to solid of 57.16 mL/g, 62.33 °C, 57.08 min, and 52.14% ethanol. The optimal extraction parameters of extracts for the highest antioxidant activity by DPPH method was a ratio of liquid to solid 60.3 mL/g, 54.56 °C, 45.59 min, and 46.67% ethanol, and by ABTS assay was a ratio of liquid to solid 47.29 mL/g, 63.73 °C, 51.62 min, and 60% ethanol concentration. Our work offers optimal extraction conditions for total flavonoids and antioxidants from alfalfa.

Waste vinegar residue as substrate for phytase production.

Waste vinegar residue, the by-product of vinegar processing, was used as substrate for phytase production from Aspergillus ficuum NTG-23 in solid-state fermentation to investigate the potential for the efficient re-utilization or recycling of waste vinegar residue. Statistical designs were applied in the processing of phytase production. First, a Plackett-Burman (PB) design was used to evaluate eleven parameters: glucose, starch, wheat bran, (NH(4))(2)SO(4), NH(4)NO(3), tryptone, soybean meal, MgSO(4)·7H(2)O, CaCl(2)·7H(2)O, FeSO(4)·7H(2)O, incubation time. The PB experiments showed that there were three significant factors: glucose, soybean meal and incubation time. The closest values to the optimum point were then derived by steepest ascent path. Finally, a mathematical model was created and validated to explain the behavioural process after these three significant factors were optimized using response surface methodology (RSM). The best phytase activity was attained using the following conditions: glucose (7.2%), soybean meal (5.1%), and incubation time (271 h). The phytase activity was 7.34-fold higher due to optimization by PB design, steepest ascent path design and RSM. The phytase activity was enhanced 0.26-fold in comparison with the results by the second step of steepest ascent path design. The results indicate that with waste vinegar residue as a substrate higher production of phytase from Aspergillus ficuum NTG-23 could be obtained through an optimization process and that this method might be applied to an integrated system for recycling of the waste vinegar residue.

Effects of dietary taurine on egg production, egg quality and cholesterol levels in Japanese quail.

BACKGROUND: Taurine is a semi-essential amino acid and has many biological properties. The objective of this study was to determine the effect of dietary supplementation with taurine on egg production, egg quality, and cholesterol level in serum and egg yolk of quails. A total of 108 quails aged 6 weeks were randomly allocated to three dietary treatments. Each treatment consisted of four replicates of nine quails. The diets were supplemented with 0, 100, and 500 mg kg(-1) of taurine for 8 weeks. RESULTS: Dietary 500 mg kg(-1) taurine significantly affected egg production rate and feed conversion ratio, but had no significant effects on body weight gain, feed consumption, or egg weight. Dietary taurine had no significant effect on egg quality parameters studied. Serum triglyceride concentration was reduced significantly with supplementation of taurine at 100 and 500 mg kg(-1). Egg yolk cholesterol content was reduced significantly, and the contents of serum taurine and egg yolk taurine were increased significantly with taurine supplementation at 500 mg kg(-1). CONCLUSION: Results of the present study indicated that adding 500 mg kg(-1) taurine reduced yolk cholesterol concentration and increased yolk taurine content without adverse effects on performance and egg quality of laying quails.

Effects of chestnut tannins on carcass characteristics, meat quality, lipid oxidation and fatty acid composition of rabbits.

Seventy two male Bianca Italiana rabbits were used to study the effects of the inclusion (0%, 0.5%, and 1.0%) of a natural extract of chestnut wood (Silvafeed ENC) in the diet on productive traits, carcass characteristics, meat quality, lipid oxidation and fatty acid composition of rabbit meat. Results showed ENC had no significant effect on live weight, productive traits, hot carcass weight, dressing percentage, skin weight, pH, cooking losses, shear force and colour. The iron content was higher in Longissimus thoracis et lumborum (LTL) muscle of rabbit fed the ENC 1.0% diet than the control group. TBARS average values in the group ENC 0.5% were significantly lower (P<0.05) than in the control and ENC 1.0% groups. Myristic acid (C14:0; P<0.01), palmitoleic acid (C16:1 cis-9; P<0.05) and pentadecanoic acid (C15:0; P<0.01) contents were lower in LTL muscle of rabbits fed the ENC 1.0% diet, whereas the palmitic acid (C16:0) content was higher (P<0.05) in the rabbits of this group. Moreover, the rabbits fed with the ENC 0.5% diet had lower (P<0.01) levels of trans-vaccenic acid (C18:1 trans-11) compared to rabbits fed with the control diet. No significant differences were observed in saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids, as well as in PUFA/SFA and n-6/n-3 ratios among the groups.