Abstract:
Poor fertility and Embryo Mortality (EM) in breeder hens have been attributed to Natural Mating (NM) system adopted by farmers in breeder hens. Artificial Insemination (AI) could be a reliable alternative for use in chickens. However, AI protocols required for optimum fertility in layer breeders were scanty. Therefore, fertility and embryo viability responses of artificially inseminated layer breeder chickens were assessed.
ISA Brown breeder hens (n=100, 1.9±0.3kg) and cocks (n=10, 2.5±0.4kg), 21-week old were used. Hens were randomly allotted to five treatments and were inseminated with 0.02 (T0.02), 0.04 (T0.04), 0.06 (T0.06) and 0.08mL (T0.08) of pooled semen/hen which contained 33×106, 66×106, 99×106, 132×106 motile spermatozoa, respectively. Hens in fifth group (TNM) were mated naturally. Both AI and NM were repeated for two consecutive days. Fertility was determined by standard method. Four groups of 25 hens each were inseminated with 0.02mL semen dose then repeated at three (D3), six (D6), nine (D9) and twelve days (D12) interval for twelve weeks. Fertility and EM were determined following standard procedures. Another batch of semen was divided into five portions: undiluted (US), diluted at 1:1, with either Modified Ringer Solution (MRS), 1% Dextrose Saline (DS), Sodium Citrate (SC) or Normal Saline (NS). In vitro assessment was done hourly at 27.6ºC till motility dropped below 50.0%. The treatments were inseminated into five groups of hens at D6 and D9 interval to assess fertility using standard procedures. The DS was divided into five portions: four portions were fortified with Carrot Juice (CJ) as extender at 25%(T25), 50%(T50), 75%(T75), 100%(T100), while DS served as control. The extenders were used to extend semen at 1:1 and evaluated hourly at 27.6ºC for Spermatozoa Motility (SM) and livability till motility was below 50%. In a 5×4 factorial arrangement, the treatments were inseminated into five groups of 20 hen at D6 interval. Fertility and EM were determined by standard procedures. Data were analysed using descriptive statistics and ANOVAα0.05.
The T0.02 (90.7%), T0.04 (95.0%), T0.06 (90.4%) and T0.08 (90.4%) significantly improved fertility than TNM (77.1%) in the first week. The efficient and maximum duration of fertile period were 7 and 21 days, respectively. Treatment D3 (91.8%), D6 (92.5%) and D9 (87.5%) improved fertility than D12 (67.6%), while D6 had the least EM (10.8%). The MRS (59.7%), DS (59.0%), and NS (60.0%) improved SM up to the third hours than SC (46.3%) and RS (46.7%). The MRS (82.5%), DS (85.3%) and NS (83.5%) improved fertility than SC (79.2%) and RS (75.5%) at D6 interval. The same trend was observed in D9 interval though fertility decreased across the treatments: MRS (68.5%), DS (68.4%), NS (60.1%), SC (57.2%) and RS (55.1%). Semen fortified with CJ sustained spermatozoa livability up to third hour than DS. Fertility significantly decreased as CJ in extender increased T25 (68.3%), T50 (61.3%), T75 (49.1%), T100 (35.3%) and DS (80.8%).
Semen dose, spermatozoa age and days of insemination influenced fertility and embryo viability. Fertility in ISA brown was depressed with dextrose saline fortification using carrot juice.
