Thanks to all the postgraduate students of the Livestock and Poultry Science department, your help and support is really appreciated guys. Bars indicate SE of the measurements……….……….6 Figure 2.3 Age in days (▲) and the amount of food required per unit body weight gain.
GENERAL INTRODUCTION
Minimal attention has been paid to the role that maternal nutrition has on offspring performance. However, there are conflicting opinions in the literature regarding the effects of maternal nutrition on offspring performance.
LITERATURE REVIEW
INTRODUCTION
BROILER-BREEDER GENETIC SELECTION
- Advancements in broiler breeder selection
- Inclusion of various breeding traits in selection programs
Genetic selection of chicken breeders for increased growth rates necessitated the development of new management practices (Peebles et al., 1998; de Beer, 2009). Chickens selected for different traits have different nutritional requirements for their optimal performance (Marcato et al., 2008).
BROILER BREEDER AMINO ACID REQUIREMENTS
- Amino acid requirements for maintenance
- Amino acid requirements for tissue growth
- Amino acid requirements for egg production
Breast meat and feathers are among the tissues to be considered for amino acid requirements when preparing poultry feed (Gous et al., 1999; Wylie et al., 2003). The lack of effects of protein or amino acids on body weight gain in broilers has also been reported in other studies (Joseph et al., 2000; Fakhraei et al., 2010; Kingori et al., 2010).
LYSINE IN BROILER BREEDER PRODUCTION
It has been reported that amino acid requirements decrease in cases where egg production decreases with breeder age (Gous & Nonis also observed no improvements in body weight gain, egg weight and percent hatching of broilers fed different dietary lysine levels at 52 and 62 weeks of age Gous & Nonis (2010) reported a more likely increase in amino acid requirements over time for high-producing broiler breeders, due to an increased amino acid deposition in the egg.
RESTRICTED VS. AD LIBITUM FEEDING IN MEAT-TYPE BIRDS
- Ad libitum feeding
- Controlled feeding
However, no differences were observed in the fertility of eggs collected from hens exposed to either of these feed restriction methods (Spradley et al., 2008). Therefore, broiler breeders' feed restriction and duration of feed restriction must be continuously adjusted according to the birds' changing selection goals and genotype (Bruggeman et al., 2005).
BROILER-BREEDER REPRODUCTIVE EFFICIENCY
The degree and timing of feed restriction are the two most important determinants of broiler breeder reproductive performance (Bruggeman et al. To successfully optimize the reproductive fitness of broiler breeders, sexual maturation must be properly managed, especially during the rearing period. (Robinson et al., 2007).
BROILER-BREEDER EGG COMPOSITION
- Eggshell
- Albumen
- Egg yolk
Eggshells supply the developing embryo with calcium by dissolving certain inner shell areas during the incubation process (Moran, 2007; Chien et al., 2009). It also regulates and maintains appropriate temperatures necessary to support potential embryonic growth and development within the egg (Chien et al., 2009). Egg albumin is consumed rapidly during the incubation process to provide amino acids necessary for the synthesis of body proteins (Muramatsu et al., 1990).
Therefore, the protein content regulates the protein synthesis of the embryo during the incubation process (Muramatsu et al., 1990). However, yolk contains more solids and is therefore richer in energy than albumin (Nelson et al., 2010).
BROILER-BREEDER REPRODUCTIVE PHYSIOLOGY
- Fertility of broiler-breeder eggs
- Incubation of broiler-breeder eggs
- Hatchability of broiler-breeder eggs
The success of broiler breeder hatchery management is determined by the percentage of eggs hatched from those laid and the number of high quality day-old chicks produced (Yassin et al., 2008). It has been reported that better hatchability is obtained from broiler breeder eggs laid during the period between 40 and 42 weeks of age (Tona et al., 2001). This delay adversely affects day-old chick quality and performance of the newly hatched chick (Tona et al., 2003).
Two of the most important factors affecting the hatching of bird eggs are fecundity and embryonic mortality (Kirk et al., 1980; Yassin et al., 2008). Other reasons for reduced hatchability of rearing eggs may be improper breeder flock management and use of incorrect incubation procedures (Yassin et al., 2008; Abudabos, 2010).
EFFECTS OF BREEDER HEN NUTRITION ON OFFSPRING
Similar results were reported by Brake et al. 1985) who observed significantly better hatchability of fertilized eggs in hens fed a low protein diet compared to hens fed a high protein diet. In contrast, Kingori et al. 2010) reported no effects of maternal dietary protein on the hatchability of eggs laid by 52-week-old native laying hens fed different dietary proteins. Prolonged storage of eggs before incubation is known to delay the hatching process (Kirk et al., 1980; Tona et al., 2003; Reijrink et al., 2010) and such a delay is often associated with a delay in the initiation of embryogenesis, with a subsequent reduction in development. embryo (Byng & Nash, 1962; Tona et al., 2003).
Therefore, the success of potential embryonic development and hatching of a healthy chick is determined by the amounts and forms of nutrients deposited in the egg by the mother hen (Brand et al., 2003). Chicks born to breeder chickens fed diets supplemented with higher vitamin D3 levels at different ages showed improvements in body weight compared to chicks born to breeder chickens fed diets supplemented with low vitamin D3 levels (Atencio et al. observed no effects of maternal nutrition on vitamin D3 levels). offspring performance for chicks derived from 52-week-old native laying hens fed different amounts of crude protein in the diet.
EFFECTS OF BREEDER HEN AGE ON PROGENY PERFORMANCE
The fact that chick quality is primarily assessed based on chick performance in different environments also adds to the complexity of finding the optimal maternal feed required to maximize chick quality (Hocking, 2007). The complexity of measuring chick performance as influenced by maternal nutrition was also reported by Kidd (2006) and de Beer (2009). A greater number of yolkless chicks at hatch was also observed in chicks from 65-week-old breeders than in chicks from 29- and 41-week-old breeders (Hudson et al., 2004).
Broilers hatched from 63-week-old breeder hens had higher slaughter yields than chicks hatched from 35- and 51-week-old breeder hens (Peebles et al., 1999b). 2004) stated that chicks hatched from young breeder hens tend to have relatively low yolk sac and heart weight, which are factors likely to reduce post-hatch performance of these chicks. 1999a) observed lower mortality rates in chicks from 35- and 51-week-old broilers, compared to chicks from 63-week-old broilers. 2001) also reported a decrease in embryonic mortality for breeders from 27 to 40 weeks of age, than that of breeders older than 40 weeks.
CHICK QUALITY AND PERFORMANCE
Umbilical condition appears to be the most important parameter in determining the quality of day-old chicks (Tona et al., 2005; Fasenko & O'Dea, 2008). Therefore, a lot of attention and effort should be focused on implementing all the safety measures necessary to achieve a high-quality day-old chicken that achieves better yields at slaughter.
DISCUSSION
Therefore, adequate maternal nutrition must be provided if production of high quality and well-performing offspring is to be achieved. However, conflicting views regarding the effects of maternal nutrition on offspring performance are found in the literature. Fisher (1998) and Gous & Nonis (2010) assumed that regardless of age or strain, egg amino acid composition is expected to be constant.
This thesis aims to investigate whether the diet of broiler breeders has any effect on the performance of the offspring, via possible changes in egg composition caused by different intake of amino acids through the mother's diet. THE EFFECTS OF LYSINE INTAKE OF MEAT CHILDREN AT AGES OF 38, 48 AND 60 WEEKS ON THE PERFORMANCE OF OFFENDERS.
INTRODUCTION
MATERIALS AND METHODS
- Parental birds and management
- Dietary treatments
- Eggs
- Chicks
- Measurements
- Statistical analysis
In each case, eggs were stored for a period of 24 hours before being placed in incubators. They were placed in two incubators with half of the eggs from each treatment in each incubator and these eggs were labeled with the treatment numbers from which they were collected. 9 chicks from breeders at 38 weeks of age and 8 chicks from breeders at 48 and 60 weeks of age were placed in each cage; to keep chicks of the same treatment group together for 21 d.
Individual chick feed intake (FI) was measured by subtracting the amount of feed remaining in the troughs (feeding) at the end of each week from the initial feed placed in the troughs (feeding) at the beginning of each week, divided by the number of birds in each fence. Individual chick body weight gain (BWG) from 7 to 21 days was measured by subtracting the 7-day body weight from the 21-day body weight divided by the number of birds present in each pen.
RESULTS
- Chicks hatched from 38-week-old breeder hens
- Feed intake
- Body weight gain
- Feed conversion ratio
- Mortality
- Chicks hatched from 48-week-old breeder hens
- Feed intake
- Body weight gain
- Feed conversion ratio
- Mortality
- Chicks hatched from 60-week-old breeder hens
- Feed intake
- Body weight gain
- Feed conversion ratio
- Mortality
Regression analysis identified no response in feed intake from days 7-21, for hatchlings from breeders fed the first four treatments (Figure 3.4). No significant response in body weight gain from days 7-21 was observed in hatchlings from breeders fed the first four treatments (Figure 3.5). Feed intake of offspring from days 7-21 showed no differences in hatchlings from breeders fed all treatment groups at 60 weeks of age (Table 3.6).
No significant response was observed in feed intake from days 7-21 of hatchlings fed the first four treatments (Figure 3.7). Chicks hatched from breeders fed all treatment groups at 60 weeks of age showed no differences in feed conversion ratio from 7-21 days (Table 3.6).
DISCUSSION
The significantly improved body weight gain from 7-21 d, of chicks hatched from 38-week-old broilers with dietary lysine intake of 800 mg/bird/d, was associated with the improved feed intake of these birds. Improvements in offspring feed intake and body weight gain from 7–21 d, in the present experiment, were mainly pronounced in chicks hatched from 38-week-old broiler hens with low dietary lysine intake (800, 930 and 950 mg /bird/d) ). A greater variation in feed intake and body weight gain was observed among chicks hatched from 38-week-old breeder hens fed 930 mg lysine/bird/d.
This may explain the offspring performance improvements observed from 7–21 d of chicks hatched from 38- and 48-wk-old broilers with low dietary lysine intake (800, 930, and 950 mg/bird/d). These improvements were no longer pronounced in chicks hatched from 60-week-old breeder hens fed similar treatments.
GENERAL DISCUSSION
Effect of broiler breeder strain and broodstock age on hatchability and fertile hatchability. Effects of dietary vitamin D3 supplementation of broiler chickens on performance and bone abnormalities of offspring. Effects of timing and duration of feed restriction during growth on reproductive characteristics in female broilers.
Effects of broiler age and length of egg storage on albumen properties and hatchability. Effect of protein and energy intake of broilers on the productivity of broiler offspring. The effect of the method of feed restriction during rearing on growth and blood stress indices in broiler rearing.
Effects of feeding program and crude protein intake during rearing on fertility of broiler females.
