Variation in plasma levels of insulin-like growth factor-I (IGF-I) in lingcod: relationships among season, size, and gonadal steroids (original) (raw)
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Suitability of Insulin-Like Growth Factor 1 (IGF1) as a Measure of Relative Growth Rates in Lingcod
2011
The effectiveness of spatial management strategies is typically evaluated through traditional biological measurements of size, density, biomass, and the diversity of species inside and outside management boundaries. However, there have been relatively few attempts to evaluate the processes underlying these biological patterns. In this study, we take the first step toward developing a relative index of body growth for lingcod Ophiodon elongatus using plasma insulin-like growth factor 1 (IGF1) with the ultimate goal of measuring spatial differences in relative growth rates. Insulin-like growth factor 1 is one of the principal hormones that stimulates growth at the cellular level in all vertebrates and shows significant relationships with body growth in many fishes. In the laboratory, we found that the level of IGF1 was related to the instantaneous growth of juvenile lingcod. In the field, we measured size, condition, and plasma IGF1 level in 149 lingcod from eight locations inside and outside marine protected areas in the San Juan Islands, Washington. The IGF1 levels in wild lingcod were highly variable from site to site for both genders, and we were able to detect differences in IGF1 across space in males. Multivariate analyses showed that the spatial patterns of IGF1 differed from those of traditional biological measurements. More work is needed to validate the relationship between IGF1 and growth in larger individuals, but our research shows the potential for IGF1 to be used as an ecological indicator.
Aquaculture, 2004
A recently developed radioimmunoassay (RIA) for measuring insulin-like growth factor (IGF-I) in a variety of fish species was used to investigate the correlation between growth rate and circulating IGF-I concentrations of barramundi (Lates calcarifer), Atlantic salmon (Salmo salar) and Southern Bluefin tuna (Thunnus maccoyii). Plasma IGF-I concentration significantly increased with increasing ration size in barramundi and IGF-I concentration was positively correlated to growth rates obtained in Atlantic salmon (r 2 =0.67) and barramundi (r 2 =0.65) when fed a variety of diet formulations. IGF-I was also positively correlated to protein concentration (r 2 =0.59). This evidence suggested that measuring IGF-I concentration may provide a useful tool for monitoring fish growth rate and also as a method to rapidly assess different aquaculture diets. However, no such correlation was demonstrated in the tuna study probably due to seasonal cooling of sea surface temperature shortly before blood was sampled. Thus, some recommendations for the 0044-8486/$ -see front matter D Aquaculture 236 (2004) 583 -592 design and sampling strategy of nutritional trials where IGF-I concentrations are measured are discussed. D
Aquaculture, 2004
The effect of temperature change on the relations between growth and plasma levels of insulinlike growth factor-I (IGF-I) and 41-kDa insulin-like growth factor binding protein (41-kDa IGFBP) were assessed in postsmolt coho salmon. An experiment was initiated by reducing the temperature from 11 to 7 8C for two groups of fish that were subsequently fed at either 0.5% or 1.0% body weight per day. Two additional groups of fish were maintained at 11 8C and fed either 1.0% or 1.75% body weight per day. Fish were weighed and measured, and plasma samples were obtained on four dates: 12, 27, 47, and 63 days after the temperature change. Plasma IGF-I values were significantly lower in cool water groups than warm water groups for the first sample, by the last sampling, there were no significant differences between groups. There were no significant differences between treatment groups for plasma 41-kDa IGFBP levels for the first sampling. Subsequently, significant differences in plasma 41-kDa IGFBP levels between fish fed at different levels, regardless of temperature, were found. On all dates, significant associations were found between growth, plasma IGF-I, and 41-kDa IGFBP for fish held in warm water; however, no such relations were found for fish held in cool water for the first two sampling dates. After 47 and 63 days in cool water, significant relations between growth, plasma IGF-I, and 41-kDa IGFBP were reestablished. These data suggest that associations 0044-8486/$ -see front matter D between growth, plasma IGF-I, and 41-kDa IGFBP were disrupted by a temperature decrease for at least 4 weeks. However, significant relations were reestablished after 47 days of temperature acclimation. These results support further investigation of plasma IGF-I and 41-kDa IGFBP as growth indicators in fish. D
Physiology and Biochemistry, 2019
Monitoring the growth of salmon during their early marine phase provides insights into prey availability , and growth rates may be linked to risks of size-dependent mortality. However, the measurement of growth rate is challenging for free-living salmon in the ocean. Insulin-like growth factor (IGF)-I is a growth-promoting hormone that is emerging as a useful index of growth in salmon. In addition, laboratory-based studies using coho salmon have shown that one of circulating IGF-binding proteins (IGFBPs), IGFBP-1b, is induced by fasting and thus could be used as an inverse index of growth and/or catabolic state in salmon. However, few studies have measured plasma levels of IGFBP-1b in salmon in the wild. We measured plasma IGFBP-1b levels for postsmolt coho salmon collected in the Strait of Georgia and surrounding waters, British Columbia, Canada, and compared regional differences in IGFBP-1b to ecological information such as seawater temperature and stomach fullness. Plasma IGFBP-1b levels were the highest in fish from Eastern Johnstone Strait and relatively high in Queen Charlotte Strait and Western Johnstone Strait, which was in good agreement with the poor ocean conditions for salmon hypothesized to occur in that region. The molar ratio of plasma IGF-I to IGFBP-1b, a theoretical parameter of IGF-I availability to the receptor, discriminated differences among regions better than IGF-I or IGFBP-1b alone. Our data suggest that plasma IGFBP-1b reflects catabolic status in postsmolt coho salmon, as highlighted in fish in Eastern Johnston Strait, and is a useful tool to monitor negative aspects of salmon growth in the ocean.
Aquaculture, 2005
Plasma growth hormone (GH), insulin-like growth factor-I (IGF-I), and insulin were measured in two groups of Salmo salar L. during a one-year study. The fish were reared under either a simulated natural photoperiod (SNP) from January to December or a regime of continuous light from January to June, followed by SNP until December (LL/SNP). Plasma GH levels during spring were low, and lower in the LL/SNP fish (b 0.9 ng ml À 1 ) than in the SNP fish (N1.9 ng ml À 1 ), although the LL/SNP grew better (0.8% per day) than the SNP fish (0.5% per day). Plasma IGF-I levels increased transiently from January (64.7 ng ml À 1 ) to maximum in late September in the LL/SNP (85.8 ng ml À 1 ) and in November in the SNP group (87.3 ng ml À 1 ). The ratio GH:IGF-I was lower in the LL/SNP group during spring when this group grew better than the SNP group. D
AFRICAN JOURNAL OF BIOTECHNOLOGY
This study aimed to show the difference in compensatory growth (CG) with different starvation and feeding periods replications, depending on the IGF-I hormone level in the blood. There were 4 treatments in 3 replications. Other indexes like food coefficient ratio (FCR), specific growth rate (SGR) and daily food intake were also examined during the experiment. Fish were fed twice a day ad libitum as follows during the 65 days. Treatment A (TA): control treatment, continues feeding. Treatment B (TB): 4 weeks of starvation and 5 weeks of re-feeding. Treatment C (TC): 3 weeks of starvation and 5 weeks of re-feeding. Treatment D (TD): 2 weeks of starvation and 5 weeks of re-feeding. Each tank contained 23 fishes in each unit with an initial mean weight (SD) of 47.19 ± 0.42 (g). Blood was sampled in IGF-I hormone concentration at the beginning of the experiment, at the end of the starvation period and every 12 days in re-feeding periods. There was no significant difference between the tre...
Androgen effects on plasma GH, IGF-I, and 41-kDa IGFBP in coho salmon (Oncorhynchus kisutch)
General and Comparative Endocrinology, 2004
Among many species of salmonids, fast growing fish mature earlier than slow growing fish, and maturing males grow faster than non-maturing ones. To study the potential endocrine basis for this reciprocal relationship we examined the in vivo effects of the androgens, testosterone (T) and 11-ketotestosterone (11-KT), on plasma growth hormone (GH), insulin-like growth factor-I (IGF-I) and 41-kDa IGF binding protein (41-kDa IGFBP) (putative IGFBP-3) in coho salmon, Oncorhynchus kisutch. Immature male and female, two-year old fish (avg. wt. 31.7 ± 0.63 g) were injected with coconut oil containing T or 11-KT at a dose of 0.1, 0.25, or 1 lg/g body weight. Blood samples were taken 1 and 2 weeks postinjection, and analyzed by immunoassay for T, 11-KT, GH, IGF-I, and 41-kDa IGFBP. Steroid treatments elevated the plasma T and 11-KT levels to physiological ranges typical of maturing fish. Plasma IGF-I and 41-kDa IGFBP levels increased in response to both T and 11-KT in a significant and dose-dependent manner after 1 and 2 weeks, but GH levels were not altered. These data suggest that during reproductive maturation, in addition to the previously demonstrated effects of the IGFs on steroidogenesis, the gonadal steroids may in turn play a significant role in regulating IGF-I and its binding proteins in fish. The interaction between the reproductive and growth axes may provide a regulatory mechanism for bringing about the dimorphic growth patterns observed between maturing and non-maturing salmonids and other species of fish.
Insulin-like Growth Factor-I (IGF-I) is a physiological mediator and a potentially important growth indicator candidate in teleost fishes. In this study, the effects of increased temperature on the growth and hepatic IGF-I gene expression in Oreochromis niloticus were evaluated. Twenty all-male fish were reared separately at temperatures below 24°C for 12 days and then water temperature in 15 aquaria was gradually raised to 30°C within a day. Growth and hepatic IGF-I gene expression in five fish were obtained before the temperature change and after 2, 5 and 7 days of increasing the water temperature. The growth rate of the fish reared in the warmer temperature for 2, 5 and 7 days was significantly increased in a time dependent manner (r = 0.93). Mean hepatic IGF-I mRNA levels in fish reared at warm temperature for 2, 5 and 7 days were elevated 1.6-, 2.5-, and 3.6-fold, respectively compared to that of fish reared at cold temperature (<24°C). The IGF-I levels were significantly elevated after at least 5 days of exposure to warm temperature, which is consistent with the idea that hepatic IGF-I gene expression can be used as a short-term growth rate indicator for O. niloticus. A significant positive correlation was observed between days of rearing at warm temperature and hepatic IGF-I levels (r = 0.92); between specific growth rate (length) and IGF-I levels (r =0.92); and between condition factor and IGF-I levels (r = 0.55). The high positive association between IGF-I mRNA and growth rate validated the assertion that hepatic IGF-I levels are sufficiently sensitive to be used as instantaneous growth rate indicator in this species of fish.