EFFECTS OF REPLACING SOYBEAN MEAL WITH GRADED LEVELS OF LINSEED (LinumusitatissimumL.) MEAL ON PRODUCTIVITY AND PRODUCT QUALITY OF LAYERS AND BROILERS

Abstract

The study was based on two experiments;Experiment Iused white leghorn layers (Paper I and Paper II) whereasExperiment IIused cobb500 broilers (Paper III and Paper IV). Experiment-I was conducted to study effect of replacing soybean meal (SBM)with graded levels of linseed meal (LSM) on feed intake, egg production and quality, fertility, hatchability and chick quality(Paper I) and egg chemical compositions, fatty acids profiles and eating quality (Paper II). Experiment-II studied feed intake, growth performance and carcass parameters of broiler chickens (Paper III) and evaluated selected blood parameters, broilers meat chemical compositions, fatty acids profiles and sensory characteristics (Paper IV). Isocaloric and isonitrogenous diets were formulated based on graded levels of LSM replacing SBM at levels of 0% (T1), 6.5% (T2), 13% (T3), 19.5% (T4) and 26% (T5) in concentrate mixture.Experiments were arranged in a completely randomized design and each treatment was replicated three times. A total of 180 white leghorn chickens and 180 day-old Cobb500 were randomly distributed to the treatments and fed with the diets for 90 days (Experiment I) and 44 days (Experiment II). Feed intake and body weight change in layer (Paper I) and broiler (Paper III) were similar (P>0.05) among respective treatment groups. However, high (P<0.05) starter phase body weight was recorded for T3 (28.1g/day) while T2 (18.12g/day), T4 (20.5g/day) and T5 (15.7g/day) had similar (P>0.05) average daily gain. FCR and mortality during starter, finisher and entire periodwere similar (P>0.05) among treatment groups but no mortality wasobserved in layers. Layers FCR was greater (P<0.05) in T5 (5.89) than T3 (4.44) and T4 (4.80). Most of the egg quality parameters,fertility, hatchability, early and mid-embryonic mortality and hen weight did not statistically differ (P>0.05) among treatments (Paper I). Egg yolk height was higher in T3 (15.9mm), T4 (15.9mm) and T5 (15.8mm) than T2 (15.1mm); yolk weight is greater in T1 (15.3g) than T2 (14.0g) and T5 (13.1g) and longer chicks were recorded in T1 (15.2cm), T2 (15.2cm), T4 (15.0cm)and T5 (15.3cm) than T3(14.6cm).The proximate compositions of egg yolk and albumen (Paper II) and breast and thigh meat (Paper IV); dry matter, crude protein, ether extract, ash, xv carbohydrate and gross energy were similar (P>0.05) among treatments, except highest (P<0.05) thigh DM was reported in T1 (28.13%) whereas the lowest (P<0.05) DM was in T4 (24.16%). High (P<0.05) albumen phosphorus content was recorded for T2 while iron concentration was greater for T4. Calcium concentration of egg yolk in T5 was higher (P<0.05) than in T2, T3 and T4. The weight of most carcasses (Paper III) were similar (P>0.05) among treatment except the weight of kidney, heart, breast, liver and abdominal fat. Kidney weight for T1 (9.3g) and T3 (10.7g) were higher (P<0.05) than for T2 (6.2g), T4 (6.6) and T5 (5.2g) (Paper III). The weight of heart for T3 (9.2g) was higher than T2 (5.3g) and T5 (5.8g) while T1, T3 and T4 were similar (P>0.05). Highest (P<0.05) breast weight was observed for T3 (380.3g) than T2 (213.7g), T4 (279.8g) and T5 (194.7g). Liver weight for T3 was greater (P<0.05) than T2 and T5. The abdominal fat content of T1 (18.2g), T2 (14g) and T3 (15.5g) were higher (P<0.05) than T5 (2.8g). Greater (P<0.05) fat weight was observed in female. The RBC, WBC, Hb, PCV, MCV, MCHC and MCH (Paper IV) were not affected (P>0.05). AST, ALT, ALP, total protein, albumin, globulin and albumin /globulin ratio were similar (P>0.05) among treatments. The triglyceride concentration in T1 was higher (P<0.05) than T3, T4 and T5. Cholesterol was greater (P<0.05) in T1 as compared to that for T2, T3, T4 and T5, and glucose was higher(P<0.01) inT3 (279.3mg/dL), and T5 (294.3mg/dL) than T1 (191.3mg/dL) and T2 (180.3mg/dL) (Paper IV). The yolk myristic acid, margaric acid, linoleic acid and ratio of n-6 to n-3 were not different (P>0.05) among treatments (Paper II). The highest (P<0.05) yolk stearic, palmitic, arachidonic and total saturated fatty acid concentrations were recorded for T3 (Paper II). Yolk poly-unsaturated FAs, linolenic acid, total n-3, elaidic acid and total MUFA concentrations were greater (P<0.05) for T4 than most of the other treatments. Greater (P<0.05) eicosatrienoic acid concentration was recorded for T2. The highest (P<0.05) concentration of palmitoleic and oleic acid were recorded for T3 (12.3mg/g, 174mg/g); T4 (12.46mg/g,171.8mg/g) andT5 (12.17mg/g, 159.13mg/g), respectively. The myristic, margaric, arachidonic, linolenic, and oleic acids, total mono-unsaturated fatty acid, total omega-3 and ratio of omega-6 to omega-3 in egg albumen were similar (P>0.05) between T4 and T5 while they were not detected in other treatment groups (Paper II). Palmitic acid content of breast and thigh meat (Paper IV) was higher (P<0.05) in T1 and T2 than the other treatments. Eliadic and stearic acids concentration in thigh meat were greater (P<0.05) in T1, T2 and T3 than T4 and T5, but no xvi difference was observed among treatments in breast meat. Oleic and linoleic acids content of thigh meat were higher (P<0.05) in T2 and T3 than the rest treatments, but their concentration in breast were not varied among treatments. Breast linolenic acid (Paper IV) was high (P<0.05) in T5 but similar in thigh meat. Total SFA showed a decreasing trend with increasing level of LSM in the ration; and it was significantly greater in T1 and T2 than T4 and T5in both breast and thigh meats. Total MUFA in thigh was higher in T2 (322.12mg/g) and T3 (318.73mg/g) than T4 (270.67mg/g) and T5 (231.05mg/g), but similar among treatments for breast meat. Total PUFA in breast was greater in T5 (216.18mg/g) than the rest treatments, but did not differ among treatments for thigh meat. The ratio of MUFA to SFA for breast and thigh (Paper IV) was higher in T4 and T5 than T1 and T2. The ratio of n 6 to n-3 showed a decreasing trend as the level of LSM replacement for SBM in the ration increased; and it was lower for T5 than the other treatments for breast meat, but statistical significance was not detected for thigh meat. Sensory score for egg (Paper II) and meat (Paper IV) sample were not different (P>0.05) among treatments. The total feed cost decreased with increasing levels of linseed meal (Paper I and Paper III). Generally, linseed meal used upto 26% levels in layers and broilers diet improves essential fatty acids of chicken eggs and meat without imposing detrimental effect on production and growth performance of chickens and with no alteration of product sensory attributes.