EFFECTS OF DIFFERENT RATIOS OF DIETARY OMEGA-6 TO OMEGA-3 FATTY ACIDS ON LAYING PERFORMANCE AND EGG QUALITY OF LOHMANN BROWN HENS

Egypt. Poult. Sci. Vol (33) (IV): (957-969) (1472) Egyptian Poultry Science Journal http://www.epsaegypt.com ISSN: 1110-5623 (Print) – 2090-0570 (On...
Author: Roland Lambert
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Egypt. Poult. Sci. Vol (33) (IV): (957-969)

(1472)

Egyptian Poultry Science Journal http://www.epsaegypt.com ISSN: 1110-5623 (Print) – 2090-0570 (On line)

EFFECTS OF DIFFERENT RATIOS OF DIETARY OMEGA-6 TO OMEGA-3 FATTY ACIDS ON LAYING PERFORMANCE AND EGG QUALITY OF LOHMANN BROWN HENS. G. A. A. Hamady Anim. Produ. Dept., Fac. of Agric., Al-Azhar University, Nasr City, Cairo, Egypt. Received: 15/11/2013

Accepted: 03/12/2013

ABSTRACT: This study was performed to investigate the effects of different dietary ratios of n-6:n-3 fatty acids on laying performance, egg quality criteria and yolk fatty acids concentration of egg during the laying period (19-34 wks of age). A total number of 90 hens of laying Lohmann brown–Lite, 19 wks old were randomly distributed into three dietary treatments of 30 hens each in three replicates The 1st treatment (T1)control diet with (40:1 n-6:n-3 ratio) without oil addition, the 2nd dietary treatment (T2) contain (14:1 n-6:n-3 ratio)by addition 5% soybean oil to the diet and the 3rd treatment (T3) contain (7:1 n-6:n-3 ratio)by addition 5% canola oil to the diet. Results obtained are summarized as follows: 1- Hens in group (T1) recorded highly significant value of average feed intake compared with others groups (T2 and T3), while the lowest value was recorded by group (T3). 2- Results revealed that the highest values of omega-3 and unsaturated fatty acids (ΣUFA) were recorded (P≤0.05) by the group (T3), while the lowest value was recorded by group (T1). The highest value of omega-6 was recorded (P≤0.05) by the group (T2). The results showed also docosahexaenoic acid (DHA) was significantly (P≤0.05) higher for the groups (T3) and (T2), respectively, while the lowest value was recorded (P≤0.05) by group (T1). 3- The group (T1) contain (40:1) n-6:n-3 ratio improved significantly (P≤0.05) the most of egg quality traits such as egg weight, yolk weight and shell weight compared with others groups, while differences in the albumen weight (g), yolk color, albumen height (mm) and haugh unit were insignificant among (T1), (T2) and (T3) groups. On the basis of the results, we concluded that using narrow ratio (7:1) n-6:n-3 in the diet of laying hens is important in producing eggs with high omega n-3 and unsaturated fatty acids which is more healthy for consumer. On the other hand, using wide ratio (40:1) n-6:n-3 led to producing eggs with less healthy for consumer.

Key Words: Laying hens, omega-6 to omega-3, production, fatty acids.

Corresponding author: [email protected]

G. A. A. Hamady

certain negative effects on human health because of their proaggregatory and proinflammatory activities. Intake of large amounts of n-6 PUFA has been described as a risk factor for coronary heart diseases. Opposite effects have been found for n-3 PUFAs: inhibition of thromboxane A2 syntheses and production of prostaglandines that cause vasodilatation (Chow, 2008 and Connor, 2000). Arachidonic acid is the major n-6 PUFA derived from linoleic acid and eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) are the major n-3 PUFA derived from α-linolenic acid. Long-chain n-6 and n-3 PUFA are the precursors of eicosanoids. Eicosanoids derived from n-6 FA are proinflammatory and those derived from n-3 FA are anti or less proinflammatory (Calder, 2006). Canola oil contains significant amounts of linoleic (22.1%) and alphalinolenic fatty acids (Rowghani et al., 2007; Antongiovanni et al., 2009; Salamatdoustnobar et al., 2009; Aydin and Dogan, 2010). Soybean oil is rich in linoleic acid (51%). Linoleic acid can be converted into long chain omega-3 fatty acids in the form of docosahexaenoic acid, docosapentaenoic acid and eicosapentaenoic acid through desaturation and elongation of fatty acids in chickens (Antongiovanni et al., 2009; Cherian et al., 2009 and Mazalli et al., 2004b). The fatty acid composition of fats used in poultry diets is reflected as well in animal products (Mazalli et al., 2004a; Fouladi et al., 2008a and Agah et al., 2010). Canola oil also increases the amount of omega-3 in the form of alphalinolenic fatty acid in egg and animal tissue (Fouladi et al., 2008b). The presence of omega-3 in the diet of food animals improves the taste of poultry meat and increases the ratio of canola oil in these animals (Sarica, 2003). Canola oil has what is now considered to be an almost perfect balance of n-6 to n-3 PUFA, the n-6 to n-3

INTRODUCTION In avian species, alpha linolenic acid, (ALA 18:3n-3) and linoleic acid (18:2n-6) cannot be synthesised in the body and have to be supplied in the diet, therefore they are called essential fatty acids (EFA). Fatty acids (FA) are the major components of chicken egg yolk lipids and constitute over 4g/egg on the average. From a nutritional standpoint, yolk FA are the major source of energy and long-chain C20 and C22 polyunsaturated fatty acids (PUFA) are essential for developing chick during embryogenesis. (Cherian, 2007 and Hell et al., 2007). Oils can be used as a source of energy in layer diets (Rowghani et al., 2007). Studies showed that oils significantly alter egg yolk lipid profiles or lipid composition ratios (Rowghani et al., 2007 and Skrtic et al., 2008). In nature, oil from flax, marine sources and canola (Brassica napus) are rich in n-3 fatty acids, Also soybean oil and corn oil are considered as rich sources for n-6 fatty acids. Chrian, (2011) indicated that all mammals synthesise saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) de novo from simple precursors such as glucose or ketogenic amino acids. Recently, Laddha et al., (2012) showed that Polyunsaturated fatty acids (PUFAs) are essential nutrients of importance for several cellular function in the body including ligands for transcription factors, precursors of signal molecules and building blocks in all cells of the body, thus n-3 fatty acids are important ingredients in the human diet for many population during thousuands of years. Additionally, PUFAs are precursors of biologically active compounds called eicosanoids. Linoleic (C18:2n-6) and alinolenic acid (C18:3n-3) are essential for humans because the human body cannot synthesize them. They are converted by enzymatic desaturation and elongation into n-6 and n-3 long chain PUFAs and eicosanoids involved in many physiological processes. Eicosanoids of n-6 series have 958

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ratio in canola oil is 2:1 which perfectly matches human requirements. The inclusion of canola oil in the diet of laying hens resulted in eggs with better proportion of n-3 PUFA. N-3 enriched eggs produced by canola oil feeding to laying hens are more valuable for human beings than ordinary commercial eggs (Shakeel et al., 2010). The objective of the present study was to investigate the effect of different levels of n-6:n-3 fatty acids ratios on performance of laying hens, egg quality traits and fatty acids composition in egg yolk.

for 16 weeks (from 19-34weeks of age). Feeds and water were offered (ad libitum) for chicks along the experimental period. The conditions of housing and management of birds for all groups were similar during the experimental period and all birds were healthy and clinically free from disease. The diets were calculated based on NRC (1994) analytical values of feedstuffs. After formulating the diets, fatty acids composition of the diets was analyzed using gas liquid chromatography (GLC). Also, Chemical analysis for crude protein (CP), ash, ether extracts (EE) and crud fibers (CF) of diets were determined using methods of (A.O.A.C., 1990). The formulations and chemical composition of the experimental diets are given in (table 1). The 1st dietary treatment (T1) contained (40:1 n-6:n-3 ratio) considered as control without any oil supplementation, the 2nd diet (T2) contained (14:1 n-6:n-3 ratio)by addition 5% soybean oil to the diet and the 3rd treatment (T3) contained (7:1 n-6:n-3 ratio) by addition 5% canola oil to the diet.

MATERIALS AND METHODS Experimental Birds and Management of the Flock: Birds and Diet: The present study was carried out at the Poultry Experimental Station, belonging to Faculty of Agriculture, AlAzhar University, Cairo, Egypt. 90 hens (Lohmann Brown-lite) at 19 weeks old were randomly distributed into three experimental groups with three replicates, 10 hens for each. Each group was housed in separate pens in battery cages in open sided cages (45 -45 cm with a height of 45 cm). One bird was placed in one cage. Average initial weight of hens at the experimental start ranged between 1565 to 1582 ±6 g. The temperature degree and humidity percentages were daily measured and recorded approximately 25 ± 2.0 Co and 40 ±3.0%, respectively. The photoperiod of 16:8 h was achieved by lighting during experimental period. The experiment lasted

Productive Performance: Body weights of laying hens were recorded at the start of experimental period at 19 weeks of age. Egg production was recorded for 112 days of each replicate; egg number and egg mass were recorded daily per replicate. Feed intake, laying rate, and feed conversion ratio were measured for replicate (10 hens) weekly. Final body weights, body weight gain and mortality rate of laying hens were recorded at the end of experimental period at 34 weeks of age.

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Table (1): Formulation and diet composition of laying hens.

Ingredients

Control (T1) 40:1 64.50 13.75 10.00 0.21 0.10 0.30 0.30 2.14 8.70 100

n-6/n-3 ratio Soybean oil Canola oil (T2) (T3) 14:1 7:1 50.29 49.29 25.75 25.75 2.27 2.27 5.50 6.50 5.00 5.00 0.14 0.14 0.30 0.30 0.30 0.30 1.75 1.75 8.70 8.70 100 100

Ground yellow corn (8.5%CP). Soybean meal (44% CP). Corn gluten meal (60% CP). wheat bran (15.7% CP). Canola oil %. Soybean oil %. L-Lysine HCL %. DL-Methionine %. *Premix %. Sodium chloride (NaCl) %. Di-Calcium phosphate %. Calcium carbonate %. Total (Kg) Calculated 18.04 18.00 18.07 Crude protein, %. 2838 2832 2853 ME Kcal /Kg diet. 0.84 0.89 0.89 Lysine, %. 0.77 0.73 0.73 Methionine+ cystein, %. 0.44 0.42 0.42 Methionine, %. 0.50 0.45 0.45 Available phosphorus, %. 3.83 3.77 3.79 Calcium, %. 2.49 3.52 3.62 Crude fiber, %. Determined % C.P %. 18.03 17.89 17.96 E.E %. 4.01 5.6 5.55 Ash %. 4.63 3.8 3.94 C.F %. 3.52 3.31 3.35 Fatty acid composition (analyzed, % of total fatty acids) n-6/n-3 ratio 40.24 14.89 7.65 *Each2.5Kg of laying premix contains.Vit A 10000000 I.U – Vit D3 2000000 I.U – Vit E 10000mg – Vit K3 1000mg – Vit B11000mg –B25000mg – B61500mg –B1210000mg – Nicotinic acid 30000mg – Pantothenic acid 10000mg – folueic acid 1000mg –Biotin250mg – Choline Chloride 50% 250000mg – Fe30000– Cu4000mg –Zn 50000mg – Manganese 60000mg– Iodine 1300mg –Selenium 100mg – Cobalt 100mg. Carrier Q.S up to 2.5kg.

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chromatography, Model Packard) 6890 GC.

Egg Quality Traits: The eggs used in egg quality measurements were obtained from a total 90 hens, total fresh eggs from each replicate (5 eggs) were collected at 34 weeks of age to measure the different criteria of egg quality. In the first all eggs were weighed individually, then the eggs were broken at its equator and the internal contents were taken for subsequent measurements. The eggshells were then washed carefully until all albumin residues were apparently discarded. The shells with inner membranes were air dried for 24 hours and shell weight was recorded. The thickness of the shell was measured at three points around the equatorial line of the egg without membrane by a micrometer to the nearest 0.01 millimeter. Shell thickness was recorded as the average of the three measurements. The yolk was separated from the albumen of the internal contents of the former egg, yolk; albumen and shell were weighed separately to the nearest 0.1gm. The yolk color was measured with the use of DSM Roche yolk color fan. Haugh unit was measured according to the method of Haugh, (1937) by measuring albumen height which was measured using tripod micrometer reading to the nearest 0.01 mm using following formula: Haugh unit = 100 log (H-1.7W 0.37+7.6). Where: H= Albumen height, W= Egg weight.

HP

(Hewlett

Statistical Analysis: Data were subjected to analysis of variance using the General Linear Models. Analysis of covariance was used for (initial body weight, final body weight, body weight gain, laying rate, average egg weight, egg mass and feed conversion ratio in table 2) in order to remove the impact of feed intake on the previous traits. Procedure using of SPSS software program package (SPSS,®1998). Significant differences among means were determined by Duncan’s multiple range test (Duncan, 1955) at 5% level of significant. RESULTS AND DISCUSSION Effect of different of n-6 to n-3 ratios on performance of Lohmann brown –Lite laying hens from 19 to 34 weeks of age: Results presented in (table 2) showed that differences in average values of initial body weights at the start of the experiment (19wks of age) among the experimental groups were insignificant, indicating the random distribution of individuals into the experimental groups. Results of (table 2) reveal that narrowing the ratio between n-6 to n-3 fatty acids decreased significantly (P≤0.05) body weight gain compared to the control group, however differences in the above mentioned trait among the (14:1) and (7:1) n-6 :n-3 treatments groups were insignificant. Analysis of variance indicated that feed intake decreased significantly (P≤0.05) with each decrease in n-6:n-3 ratios compared to the control group. So, we used the analysis of covariance on order to remove the impact of feed intake on the other traits. The analysis of covariance showed that differences among the dietary treatments for final body weight, laying rate, average egg weight, egg mass and FCR ratio were insignificant. The mortality rate did not

Fatty Acids Profile Of Yolk Egg: Five eggs from each replicate were collected to determine their fatty acid profiles of yolk lipids at the end of experimental period (34 weeks of age). The yolks were collected, cleaned from albumen and immediately frozen at -20 o C until analysis. Total lipids were extracted from egg yolk by the method of Folch et al., (1957). The FA methyl esters were prepared for determination of FA contents as reported by Pearson's Chemical Analysis of Food Eighth Edition (1981). The fatty acids were analyzed by gas 961

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record any case of death during the experimental period. In general results of (table 2) indicate that decreasing the n-6:n3 ratio decreased feed intake and consequently the body weight gain of laying hens. The birds fed addition soybean oil and canola oil diets (14:1 and 7:1 n-6:n-3) respectively, appeared to have lower feed intake. This might probably be attributed to the fact that soybean oil and canola oil make these diets less palatable. The obtained finding are in agreement with those reported by Mehmet et al.,(2012) who found that feed intake decreased significantly (P

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