In this study, 160 of Japanese quails in second laying phase were randomly divided into four treatments and four replications with 10 quails in each from 46 to 56 weeks of age. Diets were formulated to supply the nutrient requirements of Japanese quails (National Research Council [NRC], 1994). Experimental diets consisted of: T1) control (without CM), T2, T3 and T4) replacing 30, 60 and 90% of SBM with CM respectively (Table 1).

Table1. Composition
and calculated of the experimental diets composition.

¹Dicalcium phosphate contained: 16.5% phosphorous and 23% calcium; ²Vitamin premix supplied the following per kg of diet: vitamin A (retinol), 8400 IU; vitamin D3 (cholecalciferol), 1800 IU; vitamin E (tocopheryl acetate), 150 mg; vitamin K, 24 mg; B1, 8 mg; B2, 16.6 mg; B6, 13 mg; B12, 5 mg; panthothenic acid, 12 mg; niacin, 36 mg; biotin, 10 mg; folic acid, 2.2 mg; choline chloride, 128.8 mg; antioxidant, 100 mg; ³Mineral premix supplied the following per kg of diet: Fe (FeSO4, 20.1% Fe), 95 mg; Mn (MnSO4, 32.5% Mn), 120 mg; Zn (ZnO, 80.5% Zn), 120 mg; Cu (CuSO4, 30.3% Cu), 35 mg; I (KI, 58% I), 5 mg; and Se (NaSeO3, 45.5% Se), 2.2 mg.

Feed intake was recorded daily in each replicate separately and then calculated per layer, and weekly average egg weight was determined. At the end of the experiment egg mass and feed conversion ratio (FCR) were calculated (g feed/g egg mass).

Three eggs were randomly selected in each replicate for every two weeks, Albumen and yolk height and width were measured and analyzed by using EQM (Egg Quality Measurements) device (Harms & Russell, 2000). The egg quality traits evaluated including: Special egg weight, albumen index, yolk index, egg shell thickness and Haughunits (Keener et al., 2006).

At the end of the experiment 12 quills in each treatment (three in each replicate) were randomly selected and bled from the brachial vein. Blood samples were taken in no anticoagulant tube for estimating some blood parameters. The bleeding procedure was limited to 1 min or less to minimize the influence of handling stress. Tubes containing blood were centrifuged at 5000 rpm during 15 min. Serum was collected and stored at-20°C for determination of total protein, albumin, uric acid, calcium and inorganic phosphorus by spectrophotometer (Hitachi, 911). Liver enzymes: AlanineAminoTransferase (ALT), Aspartate Amino Transferase (AST), Gamma-GlutamylTransferase (GGT) and Alkaline Phosphatase (ALP) were measured by Vitros 350 autoanalyser (New York, USA; Product code 680-2153) using their accompanying commercial kits (Vitros Chemistry Products, Ortho-Clinical Diagnostics, Johnson-Johnson Company, New York, USA).Iron (Fe), Zn and Cu were measured (Zhang et al., 2008). Plasma T4 and T3 concentration were determined by Enzymun-Test T4 (Boehinger-Mannheim, Manheim-Germany) and Enzymun-Test T3, Elisa-Auto T3 respectively (International Reagents Corporation, Kobe, Japan).

Data were analyzed as a completely randomized design (CRD) using the GLM procedure (Statistical Analysis System [SAS], 2002). Duncan's multiple range test was used to compared treatments (p < 0.05).

Treatments had no significant differences in body weight change in the first and end of the experiment (p > 0.05). There was significant decrease in feed intake with increasing level of canola meal (Table 2). The decrease in feed intake associated with dietary canola meal has been found by other researchers (Leslie & Summers, 1972). In some studies, feed intake was not affected by the inclusion of CM up to 100 g kg^-1 (Payvastagan, Farhoomand, Shahrooze, Delfani, & Talatapeh, 2012). The reason for decreasing in feed intake should be related to presence of some anti-nutrients in canola meal (Mcneill, Bernard, & Macleod, 2004). Other results (Thanaseelaan, 2013) have indicated that iodine supplementation was effective in ensuring normal thyroid function and offset the toxic effects of glucosinolates. No significant differences were found between treatment 2 and control in laying performance of quills in terms of egg production, egg weight, egg mass and feed conversion ratio (Table 2), and was matched by previews studies (Sadogpan, Johrir, & Reddy, 1983). The reasons could be related to nutrients in rapeseed meal were as available as those in SBM and amino acid especially lysine and methionine levels were also in required range (Elangoavan et al., 2001).

Table 2
Effect of different dietary levels of canola meal on productive parameters of Japanese quail in total period of experiment.

Values in the same row not sharing a common superscript are significantly different (p < 0.05). T1) without CM, T2) replacing 30% of SBM with CM (contained 10% CM), T3) replacing 60% of SBM with CM (contained 20% CM), T4) replacing 90% of SBM with CM (contained 30% CM). ^*SEM - Standard errors of the mean.

Egg shell thickness and shell percentage significantly decreased by increasing canola meal levels in the diet (p < 0.05).Treatments had no significance differences in egg quality parameters (Table 3). Eggshell thickness of quails fed 10% rapeseed meal were higher than other levels of canola meal, while control group had the best eggshell thickness. The results noted that there was not any significant difference in yolk index between dietary treatments.

Table 3
Effect of different dietary levels of canola meal on egg quality of Japanese quail in total period of experiment.

Values in the same row not sharing a common superscript are significantly different (p < 0.05). T1) without CM, T2) replacing 30% of SBM with CM (contained 10% CM), T3) replacing 60% of SBM with CM (contained 20% CM), T4) replacing 90% of SBM with CM (contained 30% CM). ^*SEM - Standard errors of the mean.

Lichovnikova, Klecker, and Zeman (2000) have shown the proportion of canola meal in the diets did not affect the haughunit In contrast other studies (Blair, Robblee, Dewar, Bolton, & Overfield, 2006) have found significant effect of canola meal levels on haugh unit. Some studies have shown that the diet contained 10% canola meal had the best value in egg shell thickness and egg quality, while the other levels rapeseed meal have noted the poorest value (Lichovnikova, Klecker, & Zeman, 2000; Blair et al., 2006). However, yolk index increased after feeding 20% canola seed in diet (Najib & Al-Khateeb 2004). Some results have stated feeding canola meal up to 20% did not have any adverse effects on egg weight, yolk weight and yolk weight ratio (Gheisari, Ghayor, Egbal-Saeid, Toghyani, & Najafi, 2011). These results suggested that the utilization of nutrients from canola meal diets was similar to soybean meal (Gheisari et al., 2011). The possibility of changes in fatty acid profile of egg yolk consequent to fed canola meal inclusion in layer diets and Japanese quail (Richiter, Lemser, & Andbargholz, 1996).

Total protein concentration, albumin, uric acid and urea in serum were not affected by increasing in canola meal level (Table 4). Xu et al. (2011) noted that 10 and 15% canola meal decreased levels of serum uric acid (p < 0.01). According to Bielecka, Korol, and Puzio (2006), rapeseeds inclusion into broiler diets results in decreasing the serum uric acid level which can prove the beneficial protein metabolism. However, data from our study did not confirm the results cited above.

Table 4
Effect of different dietary levels of canola meal on blood protein concentration of Japanese quail at 56 weeks of age.

mg day^-1 Lit, 2 µg day^-1 Lit; Values in the same row not sharing a common superscript are significantly different (p < 0.05); T1) without CM, T2) replacing 30% of SBM with CM (contained 10% CM), T3) replacing 60% of SBM with CM (contained 20% CM), T4) replacing 90% of SBM with CM (contained 30% CM). ^*SEM - Standard errors of the mean.

The concentration of plasma enzymes of laying quills was unaffected by canola meal (Table 5).

Table 5
Effect of different dietary levels of canola meal on liver enzyme (Unit/ Lit) of Japanese quail at 56 weeks of age.

Alanine Amino Transferase (ALT), Aspartate Amino Transferase (AST), Alkaline Phosphatase (ALP), Gamma-GlutamylTransferase (GGT); Values in the same row not sharing a common superscript are significantly different (p < 0.05); T1) without CM, T2) replacing 30% of SBM with CM (contained 10% CM), T3) replacing 60% of SBM with CM (contained 20% CM), T4) replacing 90% of SBM with CM (contained 30% CM). ^*SEM - Standard errors of the mean.

Levels of plasma AST, ALT and GGT positively correlated with increased indicative of hepatic damage (Mondal, Das, Biswas, Samanta, & Bairagi, 2007). Thompson and Todd (1994) reported that serum AST activity begins to rise during the pre haemolytic period.

So it can be conclude that replacing 30% CM with SM could not able to produce any dystrophy in hepatic or others tissues containing these enzymes and signified that the birds were apparently healthy during the feeding trail. Some researchers have shown the changes in liver enzyme activity of blood (Pearson et al., 1983), but others did not observe this reaction (Payvastagan et al., 2012), for instance, they did not find any impact from feeding glucosinolates-extracted canola meal on AST, GGT, lipase and amylase.

Serum minerals (Table 6) were not affected by increasing in canola meal (Payvastagan et al. 2012). Leeson, Atteh, and Summers (1987) have shown that the content of serum total phosphorus and calcium were higher for birds fed canola meal rather than SBM. Leeson et al. (1987) reported that even 20% of dietary full-fat canola had no significant effect on calcium and phosphorus retention in broiler chickens .On the other hand, Talebali and Farzinpour (2005) state that the existence of phytic acid in canola seeds can cause reduction in calcium ability absorption and consequently, the feed consumption reduction.

Table 6
Effect of different dietary levels of canola meal on serum mineral Japanese quail at 56 weeks of age.

mg day^-1 Lit, 2 µg day^-1 Lit; Values in the same row not sharing a common superscript are significantly different (p < 0.05); T1) without CM, T2) replacing 30% of SBM with CM (contained 10% CM), T3) replacing 60% of SBM with CM (contained 20% CM), T4) replacing 90% of SBM with CM (contained 30% CM). ^*SEM - Standard errors of the mean.

Thyroid hormone concentrations were not affected by treatments (Table 7). The concentration of T3 and T4 were determined in order to obtain information on possible effects of isothiocyanates on the diets containing canola meal. Current results have shown that no significant differences were due to treatments (p > 0.05) in this respect. It may be related to amount of isothiocyanates in canola meal used in this study. Therefore, this may be a major reason why T3 and T4 concentration unchanged. However previous reports stated consumption of isothiocyanates is known to cause decreased levels of thyroid hormones (Xu et al., 2011).

In economical aspect, in this experiment the maximum net returns noted in quills fed diet containing 10% CM, as a substitution for SBM, followed by quills fed diets with 0, 20 and 30% CM. Naseem, Khan, and Yousaf (2006) reported decreased average diet cost with increasing dietary canola meal. Tadelle, Kijora, and Peters (2003) also reported the highest net benefit at 28% inclusion level of RSM as a replacement for Noug seed cake. Decreased net income at higher level of CM inclusion, regardless of its cheaper cost as compared to other ingredients is due to the adverse effects of CM on feed intake, egg production, egg weight, egg mass and feed conversion efficiency.

Table 7
Effect of different dietary levels of canola meal on Thyroid hormone (mmoL Lit^-1) of Japanese quail at 56 weeks of age.

Values in the same row not sharing a common superscript are significantly different (p < 0.05). T1) without CM, T2) replacing 30% of SBM with CM (contained 10% CM), T3) replacing 60% of SBM with CM (contained 20% CM), T4) replacing 90% of SBM with CM (contained 30% CM). ^*SEM - Standard errors of the mean.

*Author for correspondence. E-mail: saki@basu.ac.ir