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The culture of animal cells is one of the major aspects of science which serves as a foundation for most of our recent discoveries. The major areas of application include cancer research, vaccine manufacturing, recombinant protein production, drug selection and improvement, gene therapy, stem cell biology, monoclonal antibody production, in vitro fertilization technology, cryopreservation and in vitro production of hormones. Cells can be propagated, expanded and divided into identical replicates, which can be characterized, purified and preserved by freezing. This article reviews the basic aspects of animal cell culture for modern day research.

This study examined the potential of catfish pituitary cells to proliferate in culture media and that of hormones produced in their primary culture to induce spawning in African catfish. The trypsinized pituitary cells were cultured in three culture media RPMI 1640, McCoy 5a and M 2 media with addition of 10% fetal bovine serum. Female catfish (800±200 g) were induced using the culture medium that gave the shortest population doubling time and highest cell count (RPMI 1640). The eggs were fertilized with sperm cells in vitro. The fertilization and hatchability rates were determined. The blood samples of the induced spawners were collected at O (before injection), 3, 6, 9 and 12 h, respectively after injection. The collected samples of blood plasma were analyzed using enzyme-linked immunosorbent assay for quantitative determinations of Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH). A significant increase in the cell counts over the initial seeding density of 4.1 × 10 6 /ml after 12 h of culture was established in each of the three culture media used. The induced spawning bio-assay which served as a biochemical marker for gonadotrophin specific function showed that 97.5 g/kg of mature oocytes were spawned from cultured pituitary cells (CPC), 127.5 g/kg from induction with fresh pituitary gland (FPG) and 157 g/Kg from gonadotrophin releasing hormone analogue (Ovaprim) induced catfishes (800±200 g). The fertilization rate of cultured pituitary cells (CPC) differed significantly (P<0.05) without significant differences in hatchability (P>0.05). The results of the plasma gonadotrophin revealed that the highest levels of plasma LH and FSH were reached between 9 and 12 h of ovulation in all the inducers used. The two pituitary based hormones (FSH and LH) played complementary roles during ovulation and spawning of catfish eggs. This study provides an insight to the possibility of using hormones from the primary culture of pituitary cells to induce spawning in African catfish.

Table eggs collected at random from one-hundred and fifty layers (75-FUNAAB-Alpha and 75- ISA brown) kept at Breeding Unit, Teaching and Research Farm, Olusegun Agagu University of Science and Technology, Okitipupa at 31st, 33rd, and 35th weeks (WK) of age were analyzed for internal and external characteristics within 24 hours of laying. The data collected were subjected to analysis of variance to assess the effect of breed and age of the layers on egg quality. Breed had no significant effect (p > 0.05) on the egg weight (Ewt), egg length (EL), shell weight (SW), shell ratio (SR), albumen weight (AW), albumen ratio (AR), yolk diameter (YD) and yolk height (YH) in all the ages considered. At WK 31 breed effect was observed (p < 0.05) in egg width (EW), shell index (SI), yolk weight (YW), yolk ratio (YR), albumen height (AH) and haugh unit (HU), and higher values were observed in all the traits for ISA brown except yolk weight (YW) and yolk ratio (YR). Significant effect of breed (< 0.05) was observed in HU and AH at WK33. Shell thickness (ST) and yolk index (YI) experienced breed effect at WK 35. Breed and age had no effect on nutritional compositions of eggs. It can be concluded that breed and layer's age do have effects on some egg quality parameters.