Effects of growth hormone transgenesis on metabolic rate, exercise performance and hypoxia tolerance in tilapia hybrids (original) (raw)
Related papers
Biochemical and Biophysical Research Communications, 2000
Growth hormone (GH) has been shown to have a profound impact on fish physiology and metabolism. However, detailed studies in transgenic fish have not been conducted. We have characterized the food conversion efficiency, protein profile, and biochemical correlates of growth rate in transgenic tilapia expressing the tilapia GH cDNA under the control of human cytomegalovirus regulatory sequences. Transgenic tilapia exhibited about 3.6-fold less food consumption than nontransgenic controls (P < 0.001). The food conversion efficiency was significantly (P < 0.05) higher (290%) in transgenic tilapia (2.3 ؎ 0.4) than in the control group (0.8 ؎ 0.2). Efficiency of growth, synthesis retention, anabolic stimulation, and average protein synthesis were higher in transgenic than in nontransgenic tilapia. Distinctive metabolic differences were found in transgenic juvenile tilapia. We had found differences in hepatic glucose, and in agreement with previous results we observed differences in the level of enzymatic activities in target organs. We conclude that GH-transgenic juvenile tilapia show altered physiological and metabolic conditions and are biologically more efficient.
Journal of Experimental Biology, 1993
Homologous recombinant tilapia growth hormone (rtGH) was tested for its effects on calcium metabolism in freshwater tilapia Oreochromis mossambicus. Fish were fed an optimal ration of 5 % of their body mass per day. A positive correlation was found between the amount of food given and the branchial calcium influx. In male tilapia, the mean calcium influxes were 5.80 and 11.71 micromole h-1 100 g-1 when they were fed 2 % and 5 % food, respectively. In female fish fed 5 % food, the calcium influx was 6.20 micromole h-1 100 g-1. Calcium influx via the gills was not affected by rtGH. However, in rtGH-treated fish, the net efflux of calcium was lower than in the controls. Apparently, the calcium taken up from the water was more efficiently stored in the body. GH increased the hepatosomatic index and had mild growth-promoting effects (mass and length increases); it increased the total body calcium pool without affecting bone or scale calcium density. The chloride cell density in the operc...
Aquatic Living Resources, 1995
This work descnbes the application of a homologous radioimmunoassay (RIA) in the measurement of plasma and pituitary growth hormone levels of tilapia maintained at 20 and 26"C, using recombinant tilapia growth hormone (rtiGH). RIA sensitivity (EDYo) was 0.08 nglml and ED5" was 0.6210.02 nglml. Intra-and inter-assay coefficients of variation were 3.3 and 10.6% respectively, for a plasma sample of 1 ng/ml of tiGH. Mammalian or salmonids growth hormones, thyrotropins or tilapia prolactins did not show cross-reactivity with rtiGH antiserum. Plasma and pituitary extract of Oreochromis niloticus gave inhibition curves parallel to the rtiGH standard curve without interaction with serial dilutions either of tissue extracts or plasma from hypophysectomized tilapia. Pituitary extracts from other cichlid fish showed parallel competitive binding curves. Pituitary extracts of perciform fish exhibited a lower affinity to anti-rtiGH serum, while extracts of species from more distant families showed only negligible cross-reactivity or none at al]. The effects of water temperature on plasma concentrations and pituitary contents of GH were investigated in tilapia acclimatized to 26 and to 20°C. Measurements have been performed at the beginning and at the end of a two-week experiment. Whereas in fish from colder water plasma GH mean values were decreased, only a similar tendency was obsemed in pituitary GH contents. These results emphasize the hypothesis wich reports that the increase of growth with temperature is, at least in part, controlled by GH.
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 2003
The effect of freshwater (FW) transfer on growth and on the growth hormone (GH)yinsulin-like growth factor-I (IGF-I) axis was examined in the tilapia, Oreochromis mossambicus. Tilapia were raised in seawater (SW) for 5 months and then transferred to FW for an additional 40 days. The growth rate of the fish transferred to FW was significantly reduced compared with the growth rate of fish that remained in SW. Plasma levels of GH were significantly elevated in FW-transferred fish, as were plasma IGF-I levels. Pituitary GH and liver IGF-I mRNA levels, on the other hand, were significantly reduced in the fish transferred to FW. There was a significant correlation between body mass and mRNA levels of GH and IGF-I, but not with plasma levels of GH and IGF-I. Fish transferred to FW had significantly higher prolactin (PRL) levels than the SW control fish, although there was no difference in plasma PRL levels. Consistent 177 188 with the hyperosmoregulatory effects of PRL, mRNA levels of both PRL and PRL were significantly higher in 177 188 FW-transferred fish than in the fish in SW. These results suggest that transferring tilapia from SW to FW activates the GHyIGF-I axis, but growth is still inhibited, possibly due to the greater metabolic cost of osmoregulation in FW than in SW.
Aquaculture, 2007
The growth of aquaculture has negatively affected the environment due to the high levels of nitrogen excreted by farmed fish. Here we propose that modifying the nitrogen metabolism of the fish themselves using transgenic technology might solve the pollution problem. Growth hormone (GH) is known to increase protein retention and absorption, and is thought to reduce ammonia excretion. Thus, we produced transgenic Nile tilapia (Oreochromis niloticus) that over-expressed the GH gene throughout their bodies. Our findings showed that the food-conversion efficiency of the transgenic fish was 35% higher than that of their nontransgenic siblings. The rearing period required for the transgenic fish to reach a body weight of 20 g was about 75% of that required for non-transgenic fish that were fed the same type and quantity of food. The total amount of ammonium-nitrogen excreted by the transgenic fish was about 69% of that excreted by the wild-type fish over their lifetime. These results suggest that our transgenic approach has the potential to reduce the amount of nitrogen pollution caused by farmed fish. This strategy is a promising option for making aquaculture more 'eco-friendly'.
Revista de Biología Tropical, 2013
Little is known about the effects of the interaction of growth hormone (GH) with 17 a-methyltestosterone (17-MT) during fish growth. We evaluated this in the present study to assess the effect on fish growth. Fish in two batches of juvenile tilapia (Oreochromis niloticus) (approximately 5.0cm in length) were randomly assigned in triplicate to three treatments and a control group, distributed among 12 fiberglass tanks of 1 000L capacity (50 fish per tank) in an experiment covering a period of six weeks. The experimental groups were: a) fish treated with 17-MT and GH in mineral oil (RGH); b) fish treated with 17-MT and mineral oil without the addition of GH (R); c) fish treated with GH in mineral oil but not 17-MT (NGH); and d) fish of the control group, which were treated with mineral oil but not 17-MT or GH (N). The GH was injected into the fish at a rate of 0.625mg/g body weight. Morphometric data were recorded at the beginning of the experiment (T 0) and at 15, 30 and 45 days (T 15 , T 30 and T 45), and various indicators of growth were assessed: condition factor (K); survival percentage (S), feed conversion rate (FCR), percentage weight gain (WG) and (v) daily weight gain. The optimum dietary level was calculated assuming 5% food conversion to total weight in each group. During the experiment, the fish were provided with a commercial food containing 45% protein. The data showed that GH injection resulted in a greater weight gain in fish treated with 17-MT (the RGH treatment group), being particularly significant increase in weight during T 15 and T 30 (p<0.05). High values of K were found in the R and RGH treatments during the initial days of the experiment, which may have been a consequence of the better nutritional status affecting both weight gain and growth in body length, as a result of the additive effects of 17-MT and GH. The fish in groups not treated with 17-MT and treated with 17-MT and added GH showed greater increases in WG per day, higher K values and lower FCRs than fish in the other groups, which suggests that greater feed efficiency occurred in the hormone-treated fish. Fish in the RGH treatment showed the most growth, suggesting a possible interaction between 17-MT and injected GH.
HAYATI Journal of Biosciences, 2016
Transgenic has been known as one of the applicable methods to improve growth performance of cultured fish. This study was performed to evaluate the growth performance, survival, and body composition of the 3rd generation of growth hormone (GH) transgenic common carp (TG). Juveniles (BW: 1.53 ± 0.03 g) were reared for 60 days in 250-L glass aquarium with stocking density of 25 fishes/ aquarium. Fishes were fed with commercial feed (protein content 36%), three times a day to satiation. Growth and survival were measured every 20 days. Our results showed that TG fish has 1.49 times higher in average weight growth (p < 0.05) compared with the non-transgenic common carp (NT). Higher total feed consumption, survival, body protein content, protein and lipid retention, hepatosomatic index, and lower feed conversion ratio were also shown on TG fish compared with NT fish (p < 0.05). However, body lipid content and blood glucose level of TG fish were lower (p < 0.05) compared with the NT fish. Total ammonium nitrogen level in rearing media of TG fish was 51.78% lower (p < 0.05) than that of the NT fish. In conclusion, culturing of GH-TG common carp showed potential to achieve high productivity, efficient, and environmental-friendly aquaculture.
Aquaculture, 1996
Atlantic salmon parr and pre-smolts, reared under natural conditions in fresh water (FW) were implanted with an intraperitoneal cholesterol pellet containing either ovine growth hormone (oGH, 7 Fg/g for pre-smolts and 18 p,g/g for Parr), or no hormone for control fish, 12 or 3 months respectively before natural completion of their Parr-smolt transformation. Twelve days after treatment, fish were directly transferred into full salinity sea water (SW, 35 ppt). In FW, both parr and pre-smolts had normal daily rhythms of oxygen consumption (MO,). Treatment with oGH caused a greater increase in mean MO, in pre-smelts ( + 30%) than in parr ( + 16%), which was illustrated by an upward shift of the curves representing daily variation of oxygen demand. In addition, gill (Na+-K+)ATF'ase activity increased by +_50% in parr and + 184% in pre-smolts treated with oGH. In parr, the increased salinity caused a reduction in MO,. This effect, together with the disappearance of the rhythm of oxygen consumption in control Parr, could be regarded as the consequence of the profound physiological disturbance caused by the abrupt transfer to SW suggesting that these fish were not totally adapted to SW. The attenuated decrease in MO, in treated SW-transferred parr (-27% compared with -50% in controls) and the increase in MO,, in treated SW-transferred pre-smelts (+ 13% compared with +5% controls), underline the positive effect of oGH on SW adaptability in parr and especially pre-smolts. This interpretation is supported by the improved ionic regulation in all treated fish. Moreover, changes in the plasma ion concentrations in parr may indicate a metabolic acidosis which, at least partly, may explain the marked fall of MO, observed after SW transfer.
Growth regulation and enhancement in tilapia: basic research findings and their applications
Genetic Analysis: …, 1999
Growth manipulation in fish is one of the targets of gene transfer experiments. The aim is to produce strains with improved growth performance. The transfer of growth hormone transgenes has been successful in many fish species. Now detailed knowledge of the molecular events that control growth in fish is necessary in order to efficiently manipulate this process. We have selected tilapia for our studies because these species are suitable for basic research as well as for the development of improved strains for aquaculture. Here we review the results of basic and applied research in the field of growth control and manipulation in tilapia. Our experiments produced new scientific results on growth control in tilapia. These results were used to develop a new aquacultured line with improved growth performance. Many of these results are probably applicable to other teleosts.