Activity In Catfish Research Articles

GROWTH PERFORMANCE AND ENZYME ACTIVITIES IN CATFISH [Pangasianodon hypophthalmus] FED WITH WATER HYACINTH-BASED DIET

An alternative subtitution of pollard as an imported feed ingredient is a neccesity and one of the potential ingredients is water hyacinth (Eichhornia crassipes). This study was conducted to evaluate growth performance and enzyme activity in catfish (Pangasianodon hypophthalmus). Diet with five different levels of water hyacinth subtitute of pollard (0%, 25%, 50%, 75%, and 100%) were fed to catfish for 60 days. Seventy (70) catfish fry with average initial body weight of 2.45±0.15 g were maintained in 100cm x 80cm x 60cm aquaria. Fish fed at satiation level three times daily at 8 am, 12 pm, and 4 pm. With dietary of 25% water hyacinth, growth performance and protease activity similar to 0% treatment. Feed intake, protein digestibility, feed efficiency, protein efficiency ratio, and protease and amylase enzyme activities decreased (p<0.05) in those fed with more than 25% water hyacinth. Catfish fed 25% water hyacinth showed significantly (p<0.05) higher daily growth rate, feed efficiency and protein digestibility than those with other treatments. Based on the growth performance and enzyme activity, we can conclude that the optimum dietary level of water hyacinth subtitute pollard for fry catfish is 25%.

Cytochrome P450 induction in Ictalurus punctatus following exposure to wastewater treatment plant effluent

Induction of the cytochrome P450 enzymes in fish, measured as ethoxyresorufin-O-deethylase (EROD) activity, has been extensively used as a biomarker in assessing exposures and responses of aquatic organisms to contaminants. This study focused on whether exposure to Troy (Alabama) wastewater treatment plant (TWWTP) effluent at the Walnut Creek mixing zone, induced transcription of mRNA for cytochrome P4501A1 enzyme production and increased EROD activity in channel catfish (Ictalurus punctatus). Water from Big Creek (Barbour County, AL), regarded as least impacted by pollutants, was used as a reference source for administration of a positive control chemical (PCB – Aroclor 1254). All water samples were transported from field sites to the Troy University laboratory for conducting the study. Reverse transcriptase-polymerase chain reaction (RT-PCR) indicated the presence of compounds capable of inducing transcription of CYP1A1 mRNA in catfish liver. Increased transcription of mRNA for cytochrome P4501A1 enzyme production, confirmed by a 3-fold induction of EROD activity, was found in catfish exposed to water from the TWWTP mixing zone on Walnut Creek compared to catfish exposed to Walnut Creek Upstream. Catfish exposed to water from Big Creek treated with PCBs were found to have only slightly higher enzyme activities than those exposed to water from Big Creek Control, but a 2.7-fold EROD level was found in catfish exposed to Big Creek Control compared to Walnut Creek Upstream. Determining the induction of cytochrome P450 and subsequent enzymatic activity in catfish and other fish species common to this region could be useful early molecular warnings of possible pollution effects, beyond those methods typically used to characterize water quality.

Circadian locomotor activity in Japanese sea catfish Plotosus lineatus

To find out whether or not the locomotor activity of the Japanese sea catfish, Plotosus lineatus, shows a circadian rhythmicity, the locomotor activity of this catfish was recorded in a laboratory. All of the catfish recorded (n = 20) showed a nocturnal locomotor activity rhythm under a light–dark (LD) cycle (LD 12:12). The locomotor activity started after the light was turned off, and declined during the period of darkness. In five of the six catfish we examined, locomotor activity shifted gradually over the course of 3–4 days in order to synchronize to the LD cycle after it was advanced by 6 h. Locomotor activity persisted within a constant darkness (DD) in all eight of the catfish. The average free-running period of locomotor activity under DD lasted for 24.2 ± 0.4 h (mean ± SD). Thus, the present results demonstrate that the Japanese sea catfish has an endogenous circadian oscillator entrained by an LD cycle.

Identification of a cDNA encoding channel catfish interferon

Despite considerable advances in our understanding of teleost immunity, relatively few cytokine genes, including those for interferon (IFN), have been identified at the molecular level. In contrast, numerous studies have shown that following virus infection or exposure to double-stranded RNA, fish or fish cells produce a soluble factor that is functionally similar to mammalian IFN. A putative catfish (CF) IFN cDNA was identified by BLASTX screening of a catfish EST library generated from a mixed lymphocyte culture enriched for NK-like cells. Consistent with its designation as a putative cytokine cDNA, the 3′ non-translated region contained multiple copies of an RNA instability motif. Analysis of the deduced amino acid sequence of CF IFN showed low levels of identity/similarity to a panel of mammalian and avian IFN proteins, and markedly higher similarity to a recently identified zebrafish IFN. To determine if the identified cDNA encoded CF IFN, expression was monitored following infection of channel catfish ovary (CCO) cells with UV-inactivated catfish reovirus or exposure to double-stranded RNA, treatments which induce IFN or IFN-like activity in catfish and other species. In both cases, upregulation of putative CF IFN mRNA was detected. Moreover, upregulation of CF IFN mRNA was accompanied by the appearance of an antiviral factor in the culture medium. To confirm these results, recombinant CF IFN was synthesized in COS-7 cells and shown to have antiviral activity in CCO cells. Collectively, these results argue strongly that the identified catfish cDNA is an IFN homolog.

Induction of lauric acid hydroxylase activity in catfish and bluegill by peroxisome proliferating agents

In mammals, sensitivity to peroxisome proliferation by peroxisome proliferating agents (PPAs) appears to be correlated with inducibility of lauric acid hydroxylase activity. Bluegill and catfish have been shown to respond to PPAs by induction of lauric acid hydroxylase immunoreactive proteins (Haasch, 1996). In this investigation, induction of lauric acid hydroxylase activity was confirmed by HPLC and mass spectral analysis of specific hydroxylation products and possible species-specific differences in metabolism were investigated. Male bluegill, channel catfish and rat, were administered the model PPAs, clofibrate (200 mg kg −1, i.p.), ciprofibrate (100 mg kg −1, i.p.), or olive oil as vehicle control (both sexes of catfish), 48 h prior to hepatic, trunk kidney (catfish only) or kidney (rat) microsome preparation. In general, total metabolism of lauric acid was similar in all species, but female catfish metabolize lauric acid to a greater extent than males. Ciprofibrate treatment produced significant induction of ω- and ω-6 hydroxylation in male catfish kidney. In male bluegill liver, ω-, ω-4 and ω-5 hydroxylations were significantly induced by clofibrate treatment. The data indicate that induction of lauric acid hydroxylase cytochrome(s) P450 occurs in PPA-exposed fish which may be a consideration for environmentally-exposed responsive species.

Pituitary gonadotropin-releasing hormone (GnRH) receptor activity in goldfish and catfish: seasonal and gonadal effects

The goldfish pituitary contains two classes of gonadotropin-releasing hormone (GnRH) binding sites, a high affinity/low capacity site and a low affinity/high capacity site (Habibiet al. 1987a), whereas the catfish pituitary contains a single class of high affinity GnRH binding sites (De Leeuwet al. 1988a). Seasonal variations in pituitary GnRH receptor binding parameters, and the effect of castration on pituitary GnRH receptor binding were investigated in goldfish and catfish, respectively. In goldfish, GnRH receptors undergo seasonal variation with the highest pituitary content of both high and low affinity sites occurring during the late stages of gonadal recrudescence. The observed changes in pituitary GnRH receptor content correlate closely with responsiveness to a GnRH agonistin vivo in terms of serum gonadotropin (GTH) levels. In catfish, castration results in a two-fold increase in pituitary GnRH receptor content, which can be reversed by concomitant treatment with androstenedione, but not by the non-aromatizable androgen 11β-hydroxyandrostenedione; changes observed in GnRH receptor content correlate with variations in serum GTH levels and responsiveness to a GnRH agonist. In summary, the present study provides a clear evidence for seasonal variation in pituitary GnRH receptor activity in goldfish, and demonstrates a gonadal feedback mechanism regulating GnRH receptor activity in the catfish pituitary.

Effect of pinealectomy, eye enucleation, and melatonin treatment on ovarian activity and vitellogenin levels in the catfish exposed to short photoperiod or long photoperiod.

To investigate the relative importance of pineal, and eyes, and melatonin treatment on ovarian activity, catfish. Heteropneustes fossilis subjected to pinealectomy, eye enucleation, or both were exposed to short (LD 9:15) or long (LD 14:10) photoperiod during the different stages of the annual reproductive cycle. During the preparatory period, pinealectomy accelerated ovarian recrudescence under long photoperiod, but no effects of pinealectomy were observed under short photoperiod. Pineal has no influence on ovarian activity during the prespawning and spawning periods of the reproductive cycle. In the late postspawning period, ovarian recrudescence is accelerated after pinealectomy in catfish maintained under short photoperiod (LD 9:15 at 25 degrees C). But under long photoperiod (LD 14:10 at 25 degrees C), pinealectomy delayed ovarian recrudescence. An investigation into the role of the eyes revealed that eye enucleation nullifies the inhibitory effects of LD 9:15 and represses the stimulatory effects of LD 14:10. Combined surgery inhibited ovarian development under both the regimes. It is significant that pinealectomy and/or blinding neither counteracted nor delayed the postspawning ovarian regression. The findings suggest that the role of the pineal in catfish reproduction is variable and depends upon the photoperiod to which they are exposed as well as on the time of the year and the stage of the reproductive cycle. It is concluded that extraretinal and extrapineal photoreceptors also are involved in influencing seasonal reproduction. Further, no effects of melatonin treatment on ovarian activity or on vitellogenin levels during the preparatory or prespawning periods were observed, indicating that the pineal effects on gonadal activity in catfish may not be mediated through the secretion of melatonin.

Toxaphene inhibition of ATPase activity in catfish, ictalurus punctatus, tissues.

Toxaphene inhibition of ATPase activity in catfish, ictalurus punctatus, tissues.

Notes on the Oxygen Consumption and Activity of Catfish

Notes on the Oxygen Consumption and Activity of Catfish