Breeding under unpredictable conditions: Annual variation in gonadal maturation, energetic reserves and plasma levels of androgens and corticosterone in anurans from the Brazilian semi-arid

The objective of this work was to evaluate the effect of photoperiod on luteinizing hormone (LH) plasma levels and gonadal maturation of lambari females. One hundred and twenty adult lambaris, distributed into 12 aquaria of 20 L each, were randomly subjected to three different treatments, in a completely randomized design, and four replicates. Treatments were photoperiods in hours of light (L) and darkness (D): T1, 0 L:24 D; T2, 12 L:12 D; T3, 24 L:0 D. After 40 days, fish were subjected to fasting for 24 hours and, then, anesthetized. Immediately after slaughter, fish were weighed, and their gonads and livers were removed and weighed. Ovaries were weighed and immersed in Bouin's fixative solution for 24 hours and, then, kept in 70% alcohol until processing the material. Subsequently, the oocyte developmental stage was determined. No significant differences were observed between treatments for final weight, ovary weight, gonadosomatic index (GSI), hepatosomatic index (HSI) and LH levels. In all treatments, lambari females showed maturing ovaries with prevalence of vitellogenic oocytes. Photoperiod does not affect the LH levels and ovarian maturation in lambari females.

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Inter-annual variation of species composition of fallow vegetation in semi-arid Niger

Journal of Arid Environments ◽

10.1016/s0140-1963(03)00049-1 ◽

2004 ◽

Vol 56 (2) ◽

pp. 265-282 ◽

Cited By ~ 8

Author(s):

Alexander Wezel ◽

Eva Schlecht

Keyword(s):

Species Composition ◽

Annual Variation ◽

Fallow Vegetation ◽

Semi Arid

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Intra-Annual Variation in Benthic Organic Matter in A Saline, Semi-Arid Stream of Southeast Spain (Chicamo Stream)

Hydrobiologia ◽

10.1023/b:hydr.0000033126.66640.95 ◽

2004 ◽

Vol 523 (1-3) ◽

pp. 199-215 ◽

Cited By ~ 8

Author(s):

M.R. Vidal-Abarca ◽

M.L. Suárez ◽

R. Gómez ◽

C. Guerrero ◽

M.M. Sánchez-Montoya ◽

...

Keyword(s):

Organic Matter ◽

Annual Variation ◽

Benthic Organic Matter ◽

Southeast Spain ◽

Semi Arid

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Composition and ecological diversity of the ichthyofauna from the Namorados Dam, semi arid region of Paraíba, Brazil

Gaia Scientia ◽

10.21707/gs.v10.n04a51 ◽

2016 ◽

Vol 10 (4) ◽

pp. 671-680

Author(s):

Randolpho Savio de Araújo Marinho ◽

Jane Enisa Ribeiro Torelli ◽

Maria Cristina Crispim ◽

Dimítri Costa de Araújo Costa ◽

Gabriela Marques Peixoto ◽

...

Keyword(s):

Species Richness ◽

Arid Region ◽

Annual Variation ◽

Population Decline ◽

Northeastern Brazil ◽

Ecological Diversity ◽

Low Diversity ◽

Average Abundance ◽

Semi Arid Region ◽

Semi Arid

The aim of this study was to characterize the composition and ecological diversity of the ichthyofauna from the Namorados Dam, in the semi arid region of Paraíba, northeastern Brazil. Samples were collected between January 2006 and July 2007, in morning and afternoon shifts, using different fishing gear. Ecological diversity was calculated using diversity indexes of Shannon-Wiener (H'), richness (D') and evenness (J'), using the average abundance of the species. 176 individuals were collected throughout the analyzed period, being represented by 2 orders, 4 families of 5 species. With the exception of January 2006, the composition did not show specific changes, with equal predominance of the species Cichlassoma orientale and Steindachnerina notonota. Throughout the period of 2007, the prevalence was of the Order Perciformes, with dominance of the species C. orientale, which may have been caused by a population decline of Oreochromis niloticus. The lower diversity observed (H'=0,46) was due to the lower species richness (3) and the predominance of the species C. orientale in the same period. During the rainy seasons of 2006 and 2007 low diversity indexes were registered (H'=0,60 e H'=0,46) due to lower species richness (2 and 3), and dominance of O. niloticus and C. orientale. The dry season presented an average diversity of H'=0,90, which corresponds to a slight increase in species richness (5). We conclude that in this environment there is a weak annual variation in the fish assemblage, as well as in the species richness associated with seasonality of the region.

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Grain Yield, Crop and Basal Evapotranspiration, Production Functions and Water Productivity Response of Drought-tolerant and Non-drought-tolerant Maize Hybrids under Different Irrigation Levels and Population Densities: Part I. In Western Nebraska’s Semi-

Applied Engineering in Agriculture ◽

10.13031/aea.12870 ◽

2019 ◽

Vol 35 (1) ◽

pp. 61-81 ◽

Cited By ~ 1

Author(s):

Ali T. Mohammed ◽

Suat Irmak ◽

William L. Kranz ◽

Simon van Donk ◽

C. Dean Yonts

Keyword(s):

Grain Yield ◽

Annual Variation ◽

Production Functions ◽

Yield Response ◽

Substantial Variation ◽

Population Densities ◽

Drought Tolerant ◽

Yield Production ◽

Irrigation Levels ◽

Semi Arid

Abstract.Grain yield, crop evapotranspiration (ETc), basal evapotranspiration (ETb), ETc-yield production functions (ETYPF), and crop water use efficiency (CWUE) response of three drought-tolerant (DT) and one non-drought-tolerant (NDT) maize ( L.) hybrids to two plant population densities (PPDs) [84,000 plants ha-1 (high PPD) and 59,300 plants ha-1 (low PPD)] and three irrigation levels were researched at two semi-arid locations: North Platte (WCREC) and Scottsbluff (MAL), Nebraska, in 2010, 2011, and 2012. The irrigation levels were fully irrigated (FIT), early cutoff (ECOT), and rainfed (RFT). Precipitation in 2010 was above average, 2011 was a normal year, and 2012 was one of the driest and hottest years in Nebraska’s recorded history. Generally, DT hybrids performed better than the NDT hybrid. The performances of the DT hybrids were stronger in the driest year and driest location (MAL), especially with low PPD. ETc exhibited inter-annual variation for the same hybrid in the same location and between the two locations and also with the PPD and irrigation treatments. There were significant differences (P<0.05) between the ETc values for the same hybrids across three irrigation treatments. The grain yield response to hybrids and treatments also exhibited substantial variation for the same hybrid between the PPDs and had inter-annual variation between the years and locations. The greatest grain yields of 14.6 and 18.0 Mg ha-1 were observed with 548 and 837 mm of ETc, which were recorded for the DT hybrid H3 (high PPD) at WCREC and MAL, respectively. There were significant differences (P<0.05) in performance among the DT hybrids in performance variables (ETc, ETb, ETYPF, CWUE). In most cases, the DT hybrids produced greater grain yield than the NDT hybrid with lower ETc. In terms of ETYPF response for individual hybrids, the slope of the production functions exhibited an inter-annual variation between the hybrids and for the same hybrids between the years and location for both high and low PPDs. All hybrids exhibited a linear yield response to increasing ETc in all years at both locations with positive slopes in all cases with DT hybrids having the greatest slopes. The ETb values also exhibited a substantial variation between the hybrids, years, locations, and PPDs. Generally, DT hybrids had sizably lower ETb values than the NDT hybrid in both PPD levels. It was concluded that DT hybrids increase the grain yield production per unit of ETc in semi-arid regions not only during very dry and hot year, but also during the growing season with favorable rainfall and climate conditions. Keywords: Basal evapotranspiration, Drought-tolerance, Maize, Yield production functions.

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Annual variation in serum antibody concentrations against gastrointestinal nematodes in beef calves from semi-arid rangelands of western Canada

Veterinary Parasitology ◽

10.1016/j.vetpar.2014.06.031 ◽

2014 ◽

Vol 205 (1-2) ◽

pp. 169-174 ◽

Cited By ~ 3

Author(s):

Douglas D. Colwell ◽

Melissa A. Beck ◽

Cameron P. Goater ◽

Rao Z. Abbas

Keyword(s):

Annual Variation ◽

Serum Antibody ◽

Gastrointestinal Nematodes ◽

Western Canada ◽

Beef Calves ◽

Arid Rangelands ◽

Semi Arid

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THE PINEAL ORGAN: PHOTOPERIOD AND REPRODUCTIVE CYCLES IN THE GOLDFISH, CARASSIUS AURATUS L.

Journal of Endocrinology ◽

10.1677/joe.0.0460101 ◽

1970 ◽

Vol 46 (1) ◽

pp. 101-111 ◽

Cited By ~ 64

Author(s):

J. C. FENWICK

Keyword(s):

Plasma Levels ◽

Pineal Organ ◽

Light Exposure ◽

Gonadal Development ◽

Gonad Weight ◽

Osmotic Concentration ◽

Gonadal Maturation ◽

Goldfish Carassius Auratus ◽

Gonad Size ◽

Reproductive Cycles

SUMMARY The possible endocrine role of the pineal organ was studied in goldfish. Pinealectomized, sham-pinealectomized and intact goldfish were exposed to various artificially-maintained light regimens during different times of the year and the effects on gonad weight were observed. In addition, the thyroidal and interrenal tissues, the plasma osmotic concentration, and the plasma levels of Ca2+, Na+ and Cl− ions were studied in some of the experiments. The mean gonosomatic index (GSI = gonad weight expressed as percentage of body weight) of goldfish varied throughout the year and was greatest during the month of May. Further, the response of the gonads to increased daily light exposure (e.g. 16 hr. of light and 8 hr. of darkness as opposed to 8 hr. of light and 16 hr. of darkness) was maximal during the 3 months immediately preceding May. These results indicate that whilst gonadal maturation in goldfish is influenced by photoperiod, the efficacy of an increased light—dark ratio in stimulating gonadal maturation is subject to the time of year that it is imposed. An effect of pinealectomy on goldfish gonad size was restricted to those animals pinealectomized prior to, and held throughout the months of increased gonadal responsiveness to prolonged light (i.e. January, February, March, April and May). During these months, pinealectomized animals underwent greater gonadal development than sham-pinealectomized or intact goldfish when all experimental groups were exposed to 8 hr. light/day. The thyroidal and interrenal tissues, plasma osmotic concentration, and the plasma levels of Ca2+, Na+, and Cl− ions were not affected by pinealectomy in any of the experiments in which these parameters were tested. The pineal organ of the goldfish was found to be specifically related to gonadal size and this relationship was associated with the responsiveness of the gonads to light.

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