Growth and Feeding Responses of Male versus Female Yellow Perch (Perca flavescens) Treated with Estradiol-17β

1988 ◽  
Vol 45 (11) ◽  
pp. 1942-1948 ◽  
Author(s):  
Jeffrey A. Malison ◽  
Terrence B. Kayes ◽  
Bernard C. Wentworth ◽  
Clyde H. Amundson

In yellow perch (Perca flavescens) (initially 13–16 g total weight) fed to satiation (3.0–3.5% of body weight per day), estradiol-17β (E2) at 15 μg/g diet stimulated weight gain and food consumption of both sexes but did not influence food conversion efficiency (FCE), as measured by weight gain of fish per weight of food consumed. Females fed to satiation gained more weight, consumed more food, and had higher FCE than males. In perch fed a restricted ration (1.2% of body weight per day), the differences between the sexes in weight gain were reduced and due entirely to differences in FCE, and weight gain was not improved by E2. Spatial segregation or integration of the sexes had no influence on sex-related growth patterns in perch fed either the satiation or restricted ration. Carcass composition of perch treated for 84 d with E2 at 2, 20, or 50 μg/g diet did not differ from that of controls. These data indicate that (1) estrogens promote growth in yellow perch by stimulating food consumption, (2) female perch outgrow males because of both greater food consumption and higher FCE, and (3) growth differences between the sexes are not a consequence of intersexual competition for food.


1990 ◽  
Vol 47 (9) ◽  
pp. 1779-1787 ◽  
Author(s):  
Donna L. Parrish ◽  
F. Joseph Margraf

Since the mid-1970's, white perch Morone americana have expanded rapidly, resulting in possible major interactions with the native yellow perch Perca flavescens. We compared the food consumption rates, diet overlap, and growth of white perch and yellow perch from field data collected during 1983–85 and 1987. Food consumption rates were as much as 27% greater in white perch than in yellow perch, and were higher for both species in the central basin than in the western basin. Seasonal diet composition was most alike in summer and less so in spring and fall, when yellow perch ate more benthos or fish than did white perch. Of 48 Schoener index comparisons of diet overlap during a 3-yr period, 52% were significant (> 0.6). Although yellow perch grew faster in the central basin, reflecting the greater consumption rates, white perch did not show the similar large interbasin growth differences.



1985 ◽  
Vol 42 (10) ◽  
pp. 1627-1633 ◽  
Author(s):  
Jeffrey A. Malison ◽  
Cody D. Best ◽  
Terrence B. Kayes ◽  
Clyde H. Amundson ◽  
Bernard C. Wentworth

Our studies indicate that estrogen(s) promote growth and may mediate sexually related dimorphic growth in yellow perch (Perca flavescens). (1) Neither 17α-methyltestosterone (MT) at 1.5–60 μg/g diet nor estradiol-17β (E2) at 15–120 μg/g stimulated length or weight gain when fed for 85 d to age 0 perch that were initially 20–35 mm total length (TL) and 0.14–0.25 g total weight (TW). (2) In larger age 0 perch (initially 90–110 mm TL and 8–12 g TW), E2 at 2 or 20 μg/g accelerated length and weight gain; MT, triiodothyronine, and zeranol failed to promote growth at all doses tested. (3) E2 at 20 μg/g had differential effects when fed for 84 d to age 0 perch (initially 30–50 mm TL and 0.5–0.7 g TW) and age 1 perch (initially 90–110 mm TL and 8–12 g TW): E2 stimulated weight gain in the larger fish within the first 28 d, but did not improve growth in the smaller perch until they reached 80–100 mm TL and 5–10 g TW (after day 56). These results demonstrate that E2 promotes perch growth only after a certain size- or age-related maturational status has been reached. We suggest that this status is related to the onset of spermatogenesis, vitellogenesis, and sexually related dimorphic growth and may be linked to the maturation of hormone receptors.



1997 ◽  
Vol 54 (8) ◽  
pp. 1903-1915 ◽  
Author(s):  
S A Thayer ◽  
R C Haas ◽  
R D Hunter ◽  
R H Kushler

Zebra mussels (Dreissena polymorpha) in enclosures located in an experimental pond adjacent to Lake St. Clair, Michigan, increased sedimentation rate but had relatively minor effects on percent organic matter and percent nitrogen content of sediment. In contrast, sediment from Lake St. Clair adjacent to zebra mussels was significantly higher in carbon than that 0.5 m away. Zebra mussels increase the nutritional value of surficial sediment and provide greater structural heterogeneity, which is probably more important in causing change among zoobenthos. Zoobenthos and yellow perch (Perca flavescens) diet were dominated by dipteran larvae and leeches. Zoobenthos was significantly different between enclosures with and without zebra mussels. Treatments with zebra mussels had significantly more oligochaetes and tended to have more crustaceans (isopods and amphipods). In June, yellow perch without zebra mussels consumed significantly more zooplankton, and those with mussels had more crustaceans in their diet. Zooplankton density was greater in treatments without zebra mussels. Yellow perch with zebra mussels grew significantly more than those without mussels. Zebra mussels in the enclosures neither reproduced nor were eaten by yellow perch; hence. the observed growth differences were due to indirect effects involving zebra mussel induced changes in benthic structure and biota.



1982 ◽  
Vol 60 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Fred L. Bunnell

Data on lambing periods from 30 populations of North American mountain sheep are reviewed. Among all populations lambing begins later and duration is shorter at more northern altitudes (p < 0.00006). Correlations are enhanced (p < 0.00003) when latitude is replaced by a phenological index incorporating altitude. Termination of lambing is not correlated with latitude or with phenological index. Two broad patterns are evident. Populations feeding on vegetation of less predictable growth patterns ("desert type") have lengthy lambing seasons; populations feeding on vegetation exhibiting more predictable growth patterns ("alpine type") have shorter lambing seasons, typically two oestrous cycles in length. Definition of "types" by latitude or sheep taxonomy reveals significant differences in lambing periods, but correlations are enhanced when "types" are defined on the basis of habitat.Among taxa, birth weights are correlated with female body weight (rs = 0.87). Birth weights are heavier in extreme environments, seasonal growth patterns are expressed better in the alpine type, and early weight gain is most rapid in the northernmost subspecies. All populations show a strong central tendency with regard to peak lambing (17 May ± 6.8 days). Departures from that tendency respond more to predictability of vegetation than to thermal stress or predation pressure.



1971 ◽  
Vol 51 (1) ◽  
pp. 209-216 ◽  
Author(s):  
G. RAJARATNAM ◽  
J. D. SUMMERS ◽  
A. S. WOOD ◽  
E. T. MORAN Jr.

A study was undertaken to investigate the feasibility of hypothyroidism as an explanation for the smaller body size and lower metabolic activity of the recessive sex-linked dwarf chicken. A significant increase in body weight gain and feed intake for dwarf chicks with little change in these parameters for normal chicks receiving a diet supplemented with Protamone (brand name for iodinated casein) suggests a hypothyroidic state for the dwarfs. Similarly, a significantly lower body temperature, oxygen consumption and basal metabolic rate with a higher percentage of carcass fat in dwarf chicks as compared with normal ones supports the above hypothesis. Protamone supplementation of the diet increased body temperature and metabolic rate, and altered the carcass composition of the dwarfs to values closer to that of normal chicks, again suggesting a low thyroxine output for the dwarfs.



1977 ◽  
Vol 34 (10) ◽  
pp. 1643-1654 ◽  
Author(s):  
William A. Swenson

Measurement of walleye (Stizostedion vitreum vitreum) daily food consumption rates and prey density in Lake of the Woods, Minnesota, Shagawa Lake, and western Lake Superior showed a general relationship exists between the two variables. Daily food consumption increased from 1 to 3% of body weight at prey densities up to 400 mg∙m−3. Abundance of age 0 yellow perch (Perca flavescens) in Lake of the Woods, Minnesota, and Shagawa Lake resulted in much higher prey densities and daily food consumption to 4% of body weight. In Lake Superior where walleye fed exclusively on rainbow smelt (Osmerus mordax), prey density did not exceed 300 mg ∙m−3 and daily food consumption averaged less than 2.5% of body weight.Hourly food consumption by walleye changed in response to variation in prey availability and light intensity. Night feeding predominated during July and August when walleye fed on pelagic age 0 yellow perch. Feeding appeared to be continuous or crepuscular during June and September when larger demersal prey fish or invertebrates were eaten. Food consumption declined when prey concentrated near aquatic macrophytes and under conditions of high light intensity. Walleye daily food consumption was not influenced by a change in temperature from 20 to 15 °C.Daily food consumption of Lake of the Woods, Minnesota sauger (Stizostedion canadense) averaged less than walleye and was influenced by wave activity and prey density. Demersal prey was utilized by sauger throughout the 24 h-day. Key words: Percidae, food consumption, behavior, feeding, walleye, Stizostedion vitreum vitreum, sauger, S. canadense, light



1991 ◽  
Vol 69 (4) ◽  
pp. 964-972 ◽  
Author(s):  
Wolfgang A. Jansen

Five fish species were sampled at regular intervals in Narrow Lake, central Alberta, and examined for the prevalence and intensity of infestation by glochidia larvae of Anodonta grandis simpsoniana. Yellow perch (Perca flavescens) collected between January and May were infested with glochidia, whereas perch captured between June and October were free of larvae. The prevalence of infestation increased gradually from 86 to 95% between January and May, and the intensity of infestation increased from 5.7 to 49.4 glochidia per fish over the same period. Glochidia were found on most external body surfaces, including the gills. Glochidia attached preferentially to some anatomical areas, especially pectoral and pelvic fins. Furthermore, the relative importance of certain attachment sites differed significantly among sampling dates. Neither sex, size (length or weight), or age of perch significantly affected the intensity of infestation per fish. However, small (4.4–6.0 cm), 1- and 2-year-old fish carried more than 12 times the number of glochidia per gram of body weight than large (12.1–15.7 cm), 4- to 7-year-old fish. Both perch behavior and distribution and clam reproduction and distribution provide possible explanations for the observed patterns in the prevalence and intensity of infestation and in the distribution of the glochidia on the host.



1980 ◽  
Vol 14 (3) ◽  
pp. 253-261 ◽  
Author(s):  
M. J. L. Clapp

The bodyweight, food consumption and various biochemical and haematological parameters were measured in, and breeding and histological studies made of, groups of rats fed 6 different diets. All diets acceptably supported reproduction. 1 diet restricted body weight gain by 30%, and increased plasma alanine transaminase activity. Nephrocalcinosis was seen in females fed diets with a calcium: phosphorous ratio of <1. Levels of dietary protein were positively correlated with the incidence of renal pelvic dilatation in offspring at 7 weeks of age.



2010 ◽  
Vol 90 (1) ◽  
pp. 45-55 ◽  
Author(s):  
D Columbus ◽  
C L Zhu ◽  
J R Pluske ◽  
C F.M. de Lange

A total of 384 starter pigs were used to examine the application of exogenous phytase in high-moisture corn (HMC)-based liquid diets. Pigs were randomly assigned to 24 pens in six blocks. Pens were randomly assigned one of four HMC-based diets formulated to vary in total phosphorus (P) content (Low, Medium and High), with phytase added to only the Low P diet (Phy). Body weight gain and feed intake were monitored until body weight exceeded 20 kg. Apparent total tract digestibility of crude protein and P were measured on day 21 (Phase II) and day 42 (Phase III). At the end of the trial, two pigs from each pen were sacrificed for analysis of carcass composition and evaluation of metacarpals. Pigs fed the Phy treatment had increased digestibility of crude protein (P < 0.05) and P (P = 0.062) in Phase III, and increased metacarpal breaking strength (P < 0.01) and P content (P < 0.05). Average daily gain, feed intake, and carcass composition were not affected by treatment (P > 0.05). In conclusion, performance of starter pigs fed liquid HMC-based diets was maintained at dietary P levels below established requirements, but addition of phytase improved bone strength and mineralization. This study provides evidence for the effectiveness of phytase, and that P requirement for maximum rate of weight gain in pigs is not sufficient for maximum skeletal development.Key words: High-moisture corn, liquid feed, phosphorus, phytase, starter pigs



2005 ◽  
Vol 62 (10) ◽  
pp. 2211-2218 ◽  
Author(s):  
D Tardif ◽  
H Glémet ◽  
P Brodeur ◽  
M Mingelbier

RNA/DNA ratios and total lengths were compared to determine growth patterns of age-0 yellow perch (Perca flavescens) in managed and natural habitats of a large fluvial lake (Lake Saint-Pierre, St. Lawrence River, Quebec, Canada) over seasonal and yearly temporal scales. In 2002, the RNA/DNA ratio responded to degree-days accumulated over periods of 7–8 days before sampling, while in 2003, no relationship with temperature was established. The growth patterns obtained each year probably reflect indices responding to different limiting variables. In 2002, temperature would have been limiting, whereas in 2003, other factors such as prey availability, food quality, and competition may have influenced growth. In addition, the discrepancy between total length and RNA/DNA ratio observed in 2003 may reflect a differential time of response to limiting variables. These results together show that the two indices reflect growth at different time scales and suggest that their combination can help identify shifts between limiting environmental variables. Also, growth in managed wetlands during springtime was systematically superior to that in the natural environment, supporting the contention that managed wetlands are highly productive habitats. In natural habitats, growth rates were higher on the south shore by summer, which is consistent with the established north-south productivity gradient in Lake Saint-Pierre.



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