A Study of the Growth and Egg Production in Lines of Meat Chickens Selected for Fast and Slow Feathering

Prijono, Siti Nuramaliati (1991) A Study of the Growth and Egg Production in Lines of Meat Chickens Selected for Fast and Slow Feathering. PhD thesis, University of Glasgow.

Abstract

Seven experiments were carried out with fast and slow feathering lines of meat chickens in order to study the growth and egg production in these lines. The stock used in this study were the progeny of the second, third and fourth generation of lines divergently selected for fast and slow feathering from a grand parent line of Ross broiler breeders carrying the K gene. Almost all experiments followed a factorial design and the factors were diet, age, line and sex. The experiments were carried out at the Scottish Agricultural College, except for experiment on energy metabolism which was carried out at the Institute of Animal Physiology and Genetics Research, Edinburgh Research Station, Roslin. Generally, the birds were housed in floor pens, except for the parents after 2 2 weeks of age and the experiment at Roslin where birds were housed in cages. Water and feed were provided ad libitum from day old until the end of experiments, except for replacement parents after 25 days of age. The experiments were designed to provide information on sulphur amino acids and cystine requirements, feather growth, egg production, the genes affecting feathering, heat production, protein deposition and the partition of retained energy as protein and fat. Some previous workers demonstrated that amino acids are not 100% available in most common ingredients for poultry diets. Therefore, for experiment 1 and 2, per cent digestible amino acids were used to convert total to available amino acids. The value for these were based on tables of analyses of raw materials containing mean values for the digestibility of different amino acids. The objective of experiment 1 was to determine the effect of sulphur amino acid (SAA) intake on feather and body growth of male and female chickens in the fast and slow feathering lines. The sulphur amino acids content, and cystine in particular, of chicken feathers is high. Therefore, the intake of these amino acids has an important part to play in feather growth and body growth. The main findings of this study were SAA intake and feed conversion ratio (FCR) of the slow feathering line were significantly higher than the fast feathering line. FCR of the fast and slow feathering lines showed an improvement as the SAA level increased. The SAA requirement of the chicken for maximum efficiency was shown to be slightly higher than that for growth rate. The SAA requirements for the various traits during period I (0-20 days of age) and period II (21-50 days of age) are based on the maximum level achieved: The objective of experiment 3 was to obtain more information on feather growth of fast and slow feathering lines during the first 30 days of their life. Experiment 4 was conducted to obtain information on the performance of the fourth generation of fast and slow feathering lines. The objective of experiment 5 was to determine if two major genes were segregating in the fast and slow feathering lines. The main findings of two experiments of line crossing were that a mutation may have taken place in the selection process. Selection may have lead to an increased frequency of the mutant gene and that gene may now be segregating with K to cause the observed effects in feather growth. The mutant gene may be Ks, one of the k allele series. The objective of experiment 6 was to determine the protein deposition in feathers, meat and whole carcass (without meat) on males and females of fast and slow feathering lines over a wide range of body weights. The main findings were that the slow feathering line had more meat (% live body weight) and had a higher meat and carcass protein content, but lower feathers protein than the fast feathering line. However, no differences in abdominal fat weight was observed between lines. Experiment 7 was conducted to study the influence of feathering on the thermal resistance of the feathers, heat production and efficiency of utilisation of metabolisable energy by the slow and fast feathering lines. The main findings were that the fast feathering line had a greater feather weight than the slow feathering line. The increase in feather weight appeared to be associated with the increase in thermal resistance of the feathers, but a decrease in feather surface temperature and heat production. The fast feathering line had higher total energy retention than the slow feathering line. However, the partition of retained energy between fat and protein (% of retained energy) demonstrated that the slow line had a higher per cent of retained energy as protein (51.6% vs 42.4%) and lower per cent of retained energy as fat (48.4% vs 57 6%) than the fast line.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Animal sciences
• Date of Award: 1991
• Depositing User: Enlighten Team
• Unique ID: glathesis:1991-78219
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jan 2020 15:36
• Last Modified: 30 Jan 2020 15:36
• URI: https://theses.gla.ac.uk/id/eprint/78219