Effects of different oil sources and vitamin E in breeder diet on egg quality, hatchability and development of the neonatal offspring.(Report)

INTRODUCTION

It is known that breeder nutrition is one of the most important factors affecting quality of chick offspring, and may influence progeny growth, immunity and carcass attributes (Kidd, 2003). The nutrients required for chicken embryo development are derived from the nutrients stored in the egg, whose nutrient profile changes with the maternal diet (Cherian and Sim, 1997) and thereby creates differences in nutritional status of progeny (Ajuyah et al., 2003). From an economic analysis, Corzo and Kidd (2003) concluded that improving early chick viability via hen nutrition was profitable.

N-3 polyunsaturated fatty acid is receiving more attention in relation to food, nutritional and pharmaceutical applications because of its beneficial effects on cardiovascular health (Siddiqui et al., 2008), brain function and mental health (Gadoth, 2008), immunity (Wang et al., 2000) and inflammatory diseases (Kremer, 2000). Fish oil rich in n-3 PUFA plays different modulatory roles on immune function to corn oil, a source of n-6 PUFAs (He et al., 2007). N-3 PUFA often opposes the inflammatory effects of some n-6 PUFA (Darlington and Stone, 2001). The n-3 PUFA is highly susceptible to peroxidation (Oarada et al., 2008), especially in egg yolk which contains a lot of lipids. VE is the major fat-soluble antioxidant, which reduces lipid peroxidation and depresses oxidative stress (Guo et al., 2001; Sahin et al., 2006). Maternal supplementation of vitamin E has beneficial effects on antioxidant protection of the neonatal chick and postnatal development (Surai, 2000). There is little information about the impact of n-3 PUFA supplementation in the diet of breeder hens on egg quality, hatchability and the progeny. The objective of the present study was to investigate the effects of two different oil sources (fish oil and corn oil) and vitamin E supplementation in the maternal diet on egg quality, hatchability, lipid peroxidation of the egg yolk, and development of neonatal chick offspring.

MATERIALS AND METHODS

Birds and management

A total of 800 Avian 48, 28 wk old broiler breeders were randomly allocated to 4 groups with 4 replicates of 45 females and 5 males. The hens were housed in an environmentally controlled house with forced ventilation, cooling pads, an automatic water supply and 10-hole nest-box. The lighting program was 16 h light period every day. Management was conducted according to the recommended guideline from the company. The experiment lasted for 8 weeks.

Experimental diets

The experimental diets are shown in Table 1. The two oil sources were corn oil (CO) and fish oil (FO, AV-8.8 mg KOH/g; POV-16 meq[O.sub.2]/kg), and dietary inclusion level was 2%. The two levels of VE were 20 and 100 mg/kg. The four dietary treatments were as follows: CO+20 mg/kg VE, FO+20 mg/kg VE, CO+100 mg/kg VE and FO+100 mg/kg VE. The fatty acid profiles of different oils were analyzed by gas chromatography and are listed in Table 2. Daily feed allocation per female was based on production rate and body weight whereas for the male it was based on body weight according to the recommendations for primary breeders.

Sample collection and analysis

Egg quality : Eggs were collected daily and egg production was recorded and classified as settable, cracked, or abnormally shaped. Mortality was also recorded daily. For egg quality characteristics, 20 eggs per treatment were collected at the end of the 4th and 8th week of the experiment. The eggs were weighed, and yolks were separated using an egg separator and weighed. Albumen weight was calculated by subtracting yolk and shell weight from total egg weight. Egg shape index were determined by FHK (Fujihira Industry Co. Ltd., Tokyo, Japan). Eggshell breaking force was measured by egg shell Force Gauge (Model-II, Robotmation Co. Ltd., Tokyo, Japan). Eggshell thickness was measured in millimeters using Mitutoyo (Mitutoyo, 0-1", Kawasaki, Japan). Eggshell color was measured using an EQ Reflectometer (EQ Reflectometer, Technical Services and Supplies Co. Ltd., Tokyo, Japan). Albumen height, yolk color and Haugh unit were measured automatically by egg multitester EMT-5200 (Robotmation, Co., Ltd., Tokyo, Japan).

MDA in egg yolk : Lipid peroxidation was expressed as malondialdehyde (MDA), and the concentration of thiobarbituric acid reactive substances (TBARS) was detected by biochemical methods following the …