Influence of exogenous gonadal steroids on pubertal age of hens and internal qualities of eggs

Olufemi M. Alabi

Abstract: Ability of egg-type chickens to start laying earlier in life is a desirable trait that commercial poultry farmers always look forward to achieving. However, this may be delayed by some factors such as hormonal imbalance. There is a dearth of information on the use exogenous gonadal steroids to enhance the puberty attainment among egg-type chickens and internal qualities of eggs thereof. 144, 11-weeks old Super Black (SBL) hens and 144, 11-weeks Super Brown (SBR) hens were randomly allotted into four hormonal treatment groups with 36 hens per group each with three replicates in a randomized complete block design. The treatment groups are: T1 – with no hormone (NH; control), T2 – with Estradiol (E2) ,T3 – with Progestin (P4) and T4 – with equal combination of estradiol and progestin (EP). The steroids were injected intramuscularly at 5 mg per kg body weight of the hens. The experiment lasted 17 weeks during which data were collected on average daily feed intake (ADFI), hen-day production (HDP) and mortality rate while ages at puberty and peak production were determined with the HDP. Egg weight and some internal qualities were also measured at puberty and peak production. Data generated were subjected to analysis of variance statistically. All parameters investigated were significantly (P < 0.05) affected by steroidal treatment and strain. Hens (SBR) on P4 attained puberty and peaked earlier (149.67 and 175.33 days respectively) than hens on other treatments but with the highest mortality rate (8.33%). The weight and internal qualities of eggs were not affected by the treatments and strain. The results of this experiment suggest that exogenous gonadal steroids can be used to enhance puberty attainment among egg-type chickens in the humid tropics with the best result with the use of progestin.

Keywords: age, egg, hens, performance, puberty, sex steroid hormones

Date published: 2020-06-05