reproduction period
Recently Published Documents


TOTAL DOCUMENTS

60
(FIVE YEARS 19)

H-INDEX

8
(FIVE YEARS 1)

2021 ◽  
Vol 941 (1) ◽  
pp. 012010
Author(s):  
O V Kostenko

Abstract The article presents research results on the Russian beef production sector. As in the rest of the world, beef in the Russian market is losing the competition to pork and poultry. Beef is the most resource-intensive type of meat in terms of feed consumption and land requirements. The industry has a longer herd reproduction period and return on investment. The Russian beef market is in a long-term decline. Domestic production is declining, and imports have been declining since 2015. The level of consumer prices for beef is 1.5-2 times higher than the price for pork and poultry. According to the study results, several key factors in the industry’s recovery from the crisis were identified. It is necessary to radically increase the share of beef obtained from beef cattle. This will allow obtaining better quality meat and reducing its cost. Now the share is about 20%, while in the world, beef cattle account for 40%. The construction of food chains in beef cattle is different from other agricultural sectors. The model of a combination of vertical integration (holdings) and cooperation with small independent producers is effective. The formation of such networks can be accelerated by creating and stimulating regional clusters. Russian beef has significant competitive advantages in foreign markets. In Russia, the use of steroids, growth hormones, and feed additives that stimulate the muscle mass of livestock is prohibited. Russian government programs have proven their effectiveness in other agricultural sectors. In this case, resources are needed to support clusters and cooperation in meat food chains.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12032
Author(s):  
Lucia Rizzo ◽  
Ida Fiorillo ◽  
Sergio Rossi

The ecological physiology of anthozoans, as well as their resistance to stressors, are strongly influenced by environmental factors and the availability of resources. The energy budget of anthozoans can vary seasonally in order to find an equilibrium between the available resources and respiration, polyp activity, growth, and reproduction processes. The variation in the biochemical composition of the animal tissues in these organisms results from a combination of the productivity processes of the water column coupled with the reproductive effort and potential starvation periods of the anthozoans. Here, the seasonal variation in the polyp activity of a slow-growing passive suspension feeder, the octocoral Alcyonium acaule, as well as their carbohydrate, protein and lipid contents, was investigated in a warm temperate environment using in-situ observations and biochemical analyses. Polyp activity exhibited a significant variability that was moderately dependent on season, while an aestivation phenomenon in A. acaule (i.e., a resting period in which the anthozoan is not capable of any polyp activity) during the warmer months is clearly observed. Carbohydrate concentrations in the coral species showed a significant increase in the late winter and spring seasons, and the lipid content increased during the spring. A higher abundance of lipids and carbohydrates coincided with a higher primary productivity in the water column, as well as with the octocoral reproduction period. In late autumn, there was a depletion of these biomolecules, with protein levels exhibiting great variability across sampling times. Complex alterations driven by climate change could affect the energy fluxes that depend on the dead or alive particles that are intercepted by marine animal forests. The obtained findings show a food shortage in late summer and autumn of the benthic suspension feeder A. acaule through the integrative descriptors of the ecophysiology of these anthozoans. This research contributes to the knowledge of energy storage capabilities in benthic suspension feeders in general, highlighting the importance of understanding the limits of resistance to starvation periods through these indicators.


Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2710
Author(s):  
Maik Rehnus ◽  
Rupert Palme

The measurement of glucocorticoid metabolites (GCMs) in faeces has become a widely used and effective tool for evaluating the amount of stress experienced by animals. However, the potential sampling bias resulting from an oversampling of individuals in different states of pregnancy has rarely been investigated. In this study, we validate a noninvasive method for measuring gestagen metabolites in female mountain hares (Lepus timidus) under controlled conditions. We also measured the concentration of gestagen metabolites of females in a free-ranging population during the early breeding and post-breeding periods from 2014 to 2019. We found significant yearly variations in gestagen metabolites, which were related to the condition of the females due to the snow cover duration before and at the start of the reproduction period. GCMs were significantly influenced by the gestagen metabolite levels. These results are important for improving the interpretation of GCM concentrations in free-ranging populations during the breeding and reproductive periods.


Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 316
Author(s):  
Yulia V. Bespalaya ◽  
Olga V. Aksenova ◽  
Alexander V. Kropotin ◽  
Alexander R. Shevchenko ◽  
Oksana V. Travina

The Corbicula clam is one of the most successful invaders of aquatic ecosystems and has invaded all continents except Antarctica. The natural dispersion of Corbicula seems to be limited by low winter temperatures that fall below the lower lethal temperatures (0 to +2 °C). However, Corbicula can be found in colder regions, taking refuge in waters heated by thermal power plants. The purpose of this investigation was to study the gonadal histology, reproductive cycle, and the seasonal changes of shell size structure of the Corbicula clam populations in the warm water discharge of the Arkhangelsk thermal power plant (Northwest Russia). Samples were collected monthly from January 2017 to December 2018 and processed using traditional histological and morphological techniques. The number of reproductive periods varied from year to year. It was established that the Corbicula clam has a continuous reproduction period which may be adaptive in unstable environmental conditions. This reproductive strategy is probably aimed at increasing the reproductive success of the population. Our data expand the understanding of reproductive features of the Corbicula clam in harsh environmental conditions. These results could be applied to control, monitoring, and management measures.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Fadia Dib ◽  
Adib A. Saad ◽  
Abdellatif Ali

This research was conducted to study the reproductive cycle and fecundity of the fish Tristramella simonis in the Northern Great River (Nahr Alkabeer Alshmali) north of Lattakia city. 263 individuals were collected from the northern great river, during the period between July 2017 and June 2018. Samples were collected every 15 days using gill nets, which its pores diameter ranged from 16 to 20 mm and using cages (1 × 1 × 1 m). The total length of the collected fish ranged from 9.5 to 16.5 cm, and their weights ranged from 19.5 to 112.27 g. Samples contained (128 females) and (88 males) and (47) undetected. Results of Gonado Somatic Index (GSI) showed that the reproduction period was between April and August with three obvious peaks of maturity. Where the highest value of GSI was (10.06±8.46) % for females and (0.13 ± 0.05) % for males. Results of Hepato Somatic Index (HSI) was concurrence highly with the ecological and physiological changes, which result from changes in sexual activity during the reproductive cycle. Where the highest value of HSI attained 3.79 ± 1.86 % for females and attained 3.95 ± 1.38 % for males. In the first sexual maturity, the length attained 13.31 cm for females and (14.87 cm) for males. The sexual rate was (1: 0.7), which means 40.7 % males and 59.3 % females in the population. The absolute fecundity ranged from 940 to 1229 egg. While the relative fecundity ranged between 158- 215 egg/ g of ovary weight. Egg diameter during reproduction season ranged between 2.4- 4 mm, with several sizes, which mean a relatively long reproduction term.


2020 ◽  
Vol 110 (4) ◽  
pp. 535-541
Author(s):  
Afsaneh Soltaniyan ◽  
Katayoon Kheradmand ◽  
Yaghoub Fathipour ◽  
Davoud Shirdel

AbstractBetter performance of generalist predators, as well as an increase in their density, may be an incentive factor in the ability of the predators to exploit more than one food item or mixed diets. In this study, the effects of four pollen grains (cedar, pear, apricot, and pistachio) when provided to Neoseiulus californicus in mixed diets with prey, Tetranychus urticae, were evaluated. The result indicated that the fastest female developmental time was observed on pistachio pollen + T. urticae, together with apricot pollen + T. urticae. Females reared on the mixed diet comprising pistachio pollen reflected the longest total life span duration, while the shortest total life span was observed in those on the diet that included pear pollen. Furthermore, the lowest fecundity, as well as the shortest reproduction period, was determined on the diets that included pear pollen, while the highest fecundity and the longest reproduction period were observed in pistachio pollen + T. urticae. In addition, the intrinsic (r) and finite rate of increase (λ), net (R0) and gross (GRR) reproductive rates were highest in pistachio pollen + T. urticae. These findings have important implications for developing a comprehensive biological control program of T. urticae, which will be discussed.


2020 ◽  
Vol 10 ◽  
pp. 184798042095755
Author(s):  
Huixin Xiong ◽  
Xiancai Lu ◽  
Rucheng Wang

Schwertmannite has been considered as the host mineral and potentially excellent adsorbent of contaminates from waters, and it has various morphologies of spheroid with pincushions, whiskers, hedge-hogs, and needles. In this work, using the (high-resolution transmission and field-emission scanning) electron microscopes, we studied nanostructure, morphological evolution, and difference in chemical composition for the produced schwertmannites in the cell-rich iron solutions. All analysis results showed within cellular 36-h reproduction period, the production of only schwertmannite was examined in iron solutions at the Cl−/SO4 2− molar ratios of 0–10 and pH 3.0 ± 0.1. There were differences in two typical morphologies of “pincushions” (Cl−/SO4 2− = 0 and 3) and “hedge-hogs” (Cl−/SO4 2− = 6 and 10) for the schwertmannite nanostructures. And all final schwertmannite particles had the chemical formulas of Fe8O8(OH)8−2 x(SO4) x (1.08 ≤ x ≤ 1.66), especially as Cl−/SO4 2− = 0, the visible “pincushions” only being the outermost sections of the whole needles existing in a tightly spherical assemblage of schwertmannite. Moreover, the absence of ferrihydrite and goethite was determined in the nanodimension of these needles, though the initial Fe and SO4 2− were 5600 and of 9600 µg/mL, respectively. It could be induced by the amounts and activities of aqueous Fe, SO4 2−, and Cl− associated with cellular activities and mineral precipitation. This study will be useful for understanding the actual occurrence of iron oxyhydroxide nanostructure and better developing its potential environmental application.


Sign in / Sign up

Export Citation Format

Share Document