Regression-derived optimal milk thistle in growing quail's diet.

A study was conducted to evaluate the nutritional benefits of milk thistle (Silybum marianum) in quail nutrition as an additive containing antioxidant compounds such as silymarin. A total of 300, 14-d old Japanese quail chicks were randomly allotted to 5 treatments with 6 replicates and 10 birds each. The experimental diets, including a basal diet and 4 diets containing 10, 20, 30, and 40 g/kg milk thistle, were used from d 14 to 35 and spline and segmented models were applied to fit data. The optimized values of dietary milk thistle (breakpoints) for optimum amounts of serum albumin (ALB), total protein (TP), glucose (Glu), magnesium (Mg), calcium (Ca), phosphorus (P), iron (Fe), and water holding capacity (WHC) in meat samples, as predicted by the regression models, were 24.14, 20.00, 20.00, 24.50, 20.00, 10.43, 23.75, and 25.85 g/kg of diet, respectively, based on maximum R2 and minimum Sy.x. While the breakpoints for minimum cooking loss, drip loss, malondialdehyde after 10 and 30 d (MDA10 and MDA30), triglyceride (TG), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), cholesterol (CHOL), uric acid (UA), and creatinine (CRT) were 27.00, 15.82, 15.78, 33.09, 27.39, 17.99, 20.00, 20.00, 20.90, and 32.57 g/kg of diet, respectively. The use of spline models revealed an objective estimate of the optimal amounts of milk thistle for optimizing physiological responses in growing quails. The present analysis showed that higher dietary levels of milk thistle were needed for optimizing meat quality compared to other physiological responses.

Direct and maternal genetic effects for preinflection point growth traits and humoral immunity in quail.

Early growth traits in quails are considered as the growth performances before the inflection point which are genetically different from body weights (BW) at later stages. Moreover, in addition to growth performance, humoral immunity is moderately heritable and is considered in some breeding programs. However, estimating the direct genetic, particularly the maternal genetic correlations between growth and immunity in quail, are not studied sufficiently, which were the aims of the present study. The quails' BW were recorded at hatch (BW0) to 25 d of age with a 5-d interval and body weight gains (BWG) were measured as average growth performance of the birds in a 5-d period. Antibody titer against Newcastle disease virus (IgN) was measured through the hemagglutination inhibition (HI) test. For titration of anti-SRBC antibodies (IgY and IgM), a hemagglutination microtiter assay was used. In general, growth records in 4,181 birds and humoral immune responses in 1,023 birds were assigned to the study. The genetic parameters were estimated by single-trait analysis via Gibb's sampling. After finding the best model for each trait, multi-trait analysis was done to estimate the direct and maternal genetic correlations. Direct heritabilities (h2) were estimated to be moderate for BW (0.481-0.551) and BWG (0.524-0.557), while h2 for immune responses were low (0.035-0.079). Maternal environmental effect (c2) was only significant for BW0, BW5, and BWG0-5. Maternal heritabilities (m2) for BW and BWG were all lower than corresponding h2, ranging from 0.072 (BW25) to 0.098 (BW0). The m2 for IgN (0.098) was more than 2.5 times greater than h2 (0.040) for this trait. Direct (ra) and maternal (rm) genetic correlations between IgN-BW, IgY-BW, and IgY-BWG were negative, while ra and rm for IgM-BW, IgN-BWG, and IgM-BWG were positive. The ra between humoral immune responses were low to moderate and rm was significant only for IgY-IgM (0.339). Given positive genetic correlations in BWG-IgN and BWG-IgM as well as positive genetic correlations between both IgN and IgM with IgY, it is suggested that including the BWG in the breeding programs would directly result in the improvement of the birds' growth performance. It would also contribute indirectly to the improvement of the birds' humoral immune responses.

Mentha piperita as a promising feed additive used to protect liver, bone, and meat of Japanese quail against aflatoxin B1.

The present study was conducted to evaluate aflatoxin B1 (AFB1) detoxification effects of some medicinal plants under both in vitro and in vivo. The in vitro experiment was performed with 25 treatments in 5 replications. The samples of medicinal plants were incubated with AFB1 for 72 h, and the toxin residual in the supernatant was determined. The highest aflatoxin elimination was found to be related to peppermint (81%). Thereafter, in vivo experiment was conducted to investigate the effects of peppermint dried leaves, essential oil, and menthol on liver, bone, and meat, as well as the performance of growing Japanese quail fed diet contaminated with AFB1. A total of 640 7-day-old Japanese quails were assigned using a completely randomized design as 2 × 4 factorial arrangement with two levels of AFB1 (including 0 and 2.5 mg/kg diet) and four treatments (including no additive; peppermint powder, 20 g/kg; peppermint essential oil, 800 mg/kg; and menthol powder, 400 mg/kg). Those birds fed AFB1-contaminated diet with no additives showed the worst liver health status by considering super oxide dismutase (P = 0.0399), glutathione peroxidase (P = 0.0139), alanine aminotransferase (P < 0.0001), and aspartate aminotransferase levels (P = 0.0512). However, the supplementation of AFB1 contaminated diet with additives improved their liver health status. Menthol receiving birds showed the highest tibia strength, while the birds fed with AFB1-contaminated diet with no additives had the weakest bone strength (P < 0.0001). A significant increase was also observed in malondialdehyde level of meat by dietary inclusion of AFB1, which was well-repressed by the dietary supplementation of peppermint essential oil and menthol (P = 0.0075). Body weight gain dramatically decreased by adding AFB1 to the diet, which was recovered with the dietary supplementation of additives (P = 0.0585). According to the results of the current study, peppermint and its derivatives can be used to suppress aflatoxin effects on the liver, bone, and meat quality and to improve the performance of Japanese quails.

The effect of short, long, natural, and intermittent short photoperiods on meat-type Japanese quails.

The present study aimed to investigate the effects of short (8L:16D), long (23L:1D), natural, and intermittent short (8L(15 min L and 45 min D):16D) lighting programs from day 7 of age on the growth performance, carcass attributes, humoral immunity responses, and blood variables of growing Japanese quails through a 4-week production trial. Birds under the long lighting program were found to have 6.88, 6.24, and 5.55% more body weight compared to the natural, short, and intermittent lighting programs, respectively. Feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) have increased in those birds exposed to long photoperiod (P < 0.01). The feed conversion ratio in those birds exposed to the intermittent short lighting program improved by 6.92% compared to the long lighting program. The application of long photoperiod increased the relative weight of heart (P = 0.027), and liver and ovaries (P < 0.01), while it decreased the relative weight of breast meat (P = 0.06). Humoral immunity system has boosted in the birds exposed to intermittent short lighting program (P < 0.01). Applying the long photoperiod increased alkaline phosphatase, cholesterol, and triglyceride levels (P < 0.01), while total protein and calcium concentrations were increased using intermittent short lighting program (P < 0.01). The lowest heterophil-to-lymphocyte ratio was observed in the birds raised under the intermittent short lighting program (P < 0.001). The current study revealed that in terms of improving feed conversion ratio, health, and welfare, the intermittent short lighting program (8L (intermittent):16D) could be more appropriate and beneficial for meat-type Japanese quails.

Excess dietary tryptophan mitigates aflatoxicosis in growing quails.

A biological assay was carried out to evaluate the impact of dietary tryptophan (TRP) in aflatoxin B1 -contaminated diets (AFB1 -D) on performance, blood parameters, immunity, meat quality and microbial populations of intestine in Japanese quails. Six experimental diets were formulated to include two levels of dietary TRP; 2.9 (moderate high: MH-TRP) and 4.9 g/kg (excess: Ex-TRP); and three levels of AFB1 (0.0, 2.5, and 5.0 mg/kg). Each experimental diet was fed to the one of the six groups of birds from 7 to 35 days of age in a completely randomized design with 2 × 3 factorial arrangement. Decrease in feed intake, body weight gain and gain:feed in birds fed 5.0 mg/kg AFB1 -D was restored to the control level by 4.9 g TRP/kg of the diet. The hepatic enzymes in blood were elevated in quails fed on AFB1 -D but attenuated by 4.9 g TRP/kg of the diet (Ex-TRP; p ≤ .01). High serum uric acid in birds challenged with AFB1 significantly decreased by Ex-TRP (p ≤ .01). The skin thickness to 2,4-dinitro-1-chlorobenzene challenge suppressed by AFB1 but increased by Ex-TRP diet (p ≤ .02). The AFB1 increased the malondialdehyde in meat, whereas TRP efficiently diminished malondialdehyde production (p ≤ .01). The greatest drip loss and pH in meat were observed in the birds fed 5.0 mg/kg AFB1 -D but Ex-TRP augmented the adverse effects of AFB1 (p ≤ .01). The Ex-TRP reduced the total microbial and Escherichia coli counts (p ≤ .01). The adverse effect of AFB1 on ileal Lactic acid bacteria was completely prevented by Ex-TRP (p ≤ .03). This study showed that tryptophan supplementation could be considered as a powerful nutritional tool to ameliorate the adverse effects of AFB1 in growing quails.

Estimation of lysine requirements of growing Japanese quail during the fourth and fifth weeks of age.

A dose-response assay was conducted using broken-line regressions to estimate the lysine (Lys) requirements of quail chicks from 21 to 35 d of age. A basal diet was formulated to be adequate in all nutrients other than Lys. Incremental levels of L-Lys.HCl were added to the basal diet at the expense of a mix of cornstarch, NaHCO3, and NaCl to create 6 experimental diets containing 0.84 to 1.59% Lys. Feed intake (FI), weight gain (WG), and feed conversion ratio (FCR) responded quadratically to incremental levels of Lys (P < 0.0001). Using the linear broken-line (LBL) model, the estimated Lys requirements for WG during the fourth and fifth wk of age were 1.25 and 1.23% of diet, respectively. The corresponding values for FCR were estimated at 1.23 and 1.26% of diet, respectively. Fitting the quadratic broken-line (QBL) model, the estimated Lys requirements for WG during the fourth and fifth wk of age were 1.34 and 1.34% of diet, respectively. The corresponding values for FCR were estimated at 1.35 and 1.36% of diet, respectively. This study showed that using the QBL model as a promising way to estimate amino acids needed in the diet, the optimal Lys level to optimize performance of growing Japanese quail at the late stage of production might be 1.36% of diet, which is 105% of NRC recommendations.