Journal of Animal Research
Year:2013 | Volume:26 | Issue:2|Papers Count:8

Siberian sturgeon (Acipenser baerii) has been imported to Iran as a valuable candidate for aquaculture purpose. Since the stocking density is considered as an important stressor in aquaculture, Hence this study was conducted to investigate the impacts of its stocking densities on chronic stress using the blood cortisol level. In total, 90 specimens with 342±30 g mean weight and 45.3±1 cm total length were stocked in three densities (6, 12 and 18 specimen/tank) pending 5 months rearing period. The results showed no significant interaction among density–time parameters and cortisol level (p > 0.05), whereas solely time showed a significant correlation with cortisol level (p < 0.05). The levels of cortisol in July, August, October and November were 4.68±1.84, 23.22±4.44, 3.98±1.66 and 11.8±2.53ng/ml respectively. Mean cortisol concentrations in low, moderate and high densities obtained 7.76±3.59, 12.94±2.78 and 10.76±3.72 ng/ml, respectively that was not observed significant changes in no treatments. Results of this study can suggest that Siberian sturgeon withstand stocking density norms which are used for Iranian sturgeons.

The genus Calomyscus has long been considered monospecies and represented by the species C. bailwardi. Recently, eight geographic species have been recognized. Of which five species distributed in Iran: C. bailwardi, C. hotsoni, C. urartensis, C. elburzensis and C. grandis. A mitochondrial gene (CO1) including 637 base pairs for 25 specimens of four Calomyscus species was amplified. Maximum Parsimony, Bayesian and Maximum Likelihood analyses supported the current taxonomy of four studied Iranian species for Calomyscus, i.e., the recognition of the allopatric populations as distinct species. The molecular phylogeny derived from analyses of CO1 sequences divides the four taxa into two major clades. One clade including C. bailwardi, C. hotsoni and other clade is composed of C. elburzensis and C. grandis. The molecular data further indicated that C. elburzensis is distributed from northeast to central Iran (Razavi Khorasan, Northern Khorasan and Yazd Provinces) and separate Yazd population as an isolated geographically population from Elburze Mountains.

The effect of music on behavioral changes, mortality percentage and some of physiological  indices of Rainbow Trout (Oncorhynchus mykiss) in weight group of 50 ± 2 g, in  three stages with the duration of 120 h was studied. At the first stage, in order to chose the type of music, fishes were exposed to three types of classical , traditional Iranian music and sound of water flow in nature everyday. At the second stage in order to determine the time of exposure, the selected music was played for duration of 1, 3 and 6 hours per day. Based on behavioral parameters, including slow swimming near and under speaker with significant reduction in blood cortisol during the first 24 hours (22.41±1. 7 to 12.48 ± 0. 6 ng/ml) (P<0.05) and no mortality during the test, classical music was selected at the first stage. At second stage , according to the same changes  in behavioral parameters and  significant decrease in blood cortisol (30.23 ± 2.1 to 16.65 ± 1.2 ng/ml) (P<0.05) and no mortality , the period of 1 hour for classical music was selected. In the third stage of the test, based on the results of the first two stages, to evaluate the quality of the results in a recirculating system the classical music with duration of one hour per day was played for rainbow trout. Behavior changes, including slow swimming near and under  the speaker with no mortality and significant reduction in blood cortisol in hours of 0, 12, 24, 72 and 120 (37.80 ± 2.1, 32.69 ± 2.8, 20.93 ± 1.3,20.13 ± 1.5 and 11.62 ± 0.8 ng/ml respectively), glucose, (67.00 ± 4.1 , 60.66 ± 2.2, 57.11± 4.9, 53.33 ± 3.6 and 31.94 ±1.3 mg/dl respectively) (P<0.05) and a significant increase in Hepatosomatic index (HSI) (0.96 ± 0.07, 1.21 ± 0.06 , 1.26 ± 0.06 , 1.27 ± 0.07 and 1.28 ± 0.06 % respectively) (P<0.05), is positive effect of classical music on improvement of physiological mechanism and calm increase in the fishes that we can attribute.

Length-weight relationships (LWR) were calculated for 531 fish specimens from six populations of Aphanius sophiae and four populations of A. vladykovi to assess effect of sexuality and environment. The b value was 3.332 for all population of A. sophiae (95% cl = 3.276–3.390) and 3.407 for all population of A. vladykovi (95% cl = 3.342–3.472) which is placed within the expected range (2.5 – 3.5) and showed positive allometry for both species. Also there were significant differences between sexes in three out of six A. sophiae populations for b value (p>0.05), whereas no significant differences were appeared for the four A. vladikovi populations (p<0.05). It was clear that range of b value is high within different population. The results revealed that habitat and sex are two effective factors for assessment of LWR in these species and ignoring them lead to inaccurate results.

In regarding to study the fecundity and spawning season of Nemipterus japonicus in Khuozestan coastal, 482 specimens of this species were collected monthly by trawl net from Jun 2005 to May 2006 in Khuozestan coastal. Biometric characteristic such as measurement of fork length, weight and body depth was done, in order to specify spawning time, determining the sex maturity stage, ova diameter and gonadosomatic index (GSI). Ovaries were preserved and transferred to the lab taking the available standard methods into account before estimating the fecundity. The maximum and minimum estimated fecundity were 131321 and 10321 in samples with fork length 219 and 178 mm respectively. Maximum relative fecundity was 713.54 and the minimum was 55.81 in fishes with 191 and 178 mm of fork length respectively. Considering the ova diameter in different stage maturity and variation of GSI in different months, indicates that Nemipterus japonicus starts spawning between middle and end of spring. Results indicated that absolute fecundity had the highest correlation related to gonad weight (r= 9.95) and relative fecundity had the highest correlation related to gonadosomatic index (r= 9.94).

Vermicompost is one of the most nutritious organic compost which is produced by some species of earthworms such as (Eisenia foetida) and has several applications in plant cultivation. Increase in flowering and product, decrease in germination time are some examples of its application. Because of enormous amount of protein and vitamin in earthworm, it can be used as a new source of food complementary for fowl and fish. The importance of earthworm in garbage recycling is also taken into consideration. By controlling culture environmental parameters such as pH, moisture and temperature, 300 earthworms were placed in its appropriate media, to produce vermicompost in 75 days. Chemicals analysis between vermicompost produced in this research showed better quality than usual agricultural composts. Because the percentages of nitrogen, potassium, calcium, iron and zinc are higher in the vermicompost. The results showed the abundance of organic materials such as 15 amino acids (Arg, Ser, Met, His, Asp, Leu, Gly, Tyr, Glu, Phe), 2 essential fatty acids, sugars and vitamins (Niacin, Riboflavin, Pentoic acid, Thiamin, Folic acid, Biotin, B12 and B6). Thus, earth worms flour may be used in plant cultivation and also as a new source of food complementary for fowl and fish.

Evolutionary altruism has been a serious problem for evolutionary theory from its earliest times at mid-nineteen century. Group selection theory was its solution until 1960s.But at that time it was criticized so that it was no longer the solution to that problem. Since then theories put forward to solve the problem by individual and/or gene selection theories. Kin selection, reciprocal altruism, evolutionary game theory, the selfish gene, and indirect reciprocity are the main theories of this sort. Altruism according to these theories is apparent not real. Multi-level selection theory is introduced since 1970s that defends "new" group selection theory. In addition cultural group selection theory has come into the field. Altruism according to these theories is real. I agree with the second type of theories that real altruism has been evolved. But perhaps more in agreement with the first type I see it in the "shadow" of evolutionary egoism.

Stock assessment and production of fish species was carried out from November 2008 to October 2009 in the Shadegan wetland. Samples were collected from at seven stations, Mahshar, Rogbe, Khorosy, Canal, Ateish, sarakhieh and Abadan road in the Shadegan wetland in Khuzestan provinces. During one year study were measured more than 2000 specimen fish and depletion method was used for fish stock assessment.  Maximum and minimum biomass (season) was measurement in Spring (249.61 kg/ha/year) and winter (157.90 kg/ha/year) respectively. Maximum and minimum fish biomass (species) and fish production (species) were Cyprinus carpio, Thrssa ilisha and Barbus luteus, Thrssa ilisha respectively. Fish production and biomass in wetland Shadegan were estimated 130.41 (kg/ha/year) and 197.7 (kg/ha/year) respectively.