International Journal of Aquaculture, 2017, Vol.7, No.14, 94-100
99
Figure 4 Photomicrograph of (negrosin and eosin) stained milt smear (×100) of
Clarias gariepinus
, with high number of
morphologically normal but dead cells
4.5 Post collection examination
4.5.1 Test group (testis dipped in sodium (Na) citrate)
The left testes was carefully placed in a sterile container containing trisodium citrate, kept in an ice pack before
being transferred to the freezer. The sack was carefully punctured daily to collect a drop of semen to observe
motility, mass activity, and life/dead ratio for a period of 7 days.
4.5.2 Control group (milt + Na citrate)
A one in ten (1 in 10) dilution of milt was made with trisodium citrate. This was carefully aspirated into seven (7)
insulin syringes at 0.1 ml mark each, labeled accordingly and kept in an ice pack before transfer and storage in a
refrigerator at 4°C. This was also examined for a period of 7 days for the same parameters.
4.6 Statistical method
The statistical tests used for analysis here is the student T-test, pearson correlation analysis. Results were
expressed as means and standard error of mean (SEM) data was analyzed using the student T-test with SPSS/PC
computer programme, version 16.0. Differences with confidence values of P < 0.05 were considered statistically
significant. Pearson correlation analysis was also done to establish strength of positive or negative relationship
between the two groups.
5 Conclusions
Na citrate still remains a suitable buffer for short term storage of milt of African catfish but as used in this
research has to be at 4°C. The importance of dilution of milt with a suitable extender before storage cannot be
over emphasized as indicated by the result in test group irrespective of the emphasis on the dilution of milt, the
test group wasn’t totally a right off as it showed that milt can be preserved in testes after collection, as long as it is
at -20°C and does not exceed 3 days. It was recommended that farmers collect the sperm sac (testes) a day or two
days before spawning, determine the quality of the semen and store in a deep freezer before injecting the females.
A number of times local farmers inject the female brood stocks, do the proper timing, only to sacrifice the male
brood stock at the appointed time and it will not have a suitable sperm sac or good semen to complete the
synchronous reproductive process. This leads to enormous economic loss and frustration. More efforts should be
made towards establishing suitable freezing protocols for the milt of the African catfish.
Authors’ contributions
Nwankwo, P. carried out the milt collection and determination of physical characteristics of samples. Orokpo, I. carried out Pre and
Post storage collection parameters examinations. Okere, N. participated in design of study, performed the statistical analysis and
