Gender status effect on carcass and meat quality traits of feedlot Angus × Nellore cattle

The study evaluated the effect of gender status on carcass and meat quality of feedlot Angus × Nellore cattle. A total of 176 cattle, 20 months old, were confined for 190‐days and assigned to four treatments: bulls, immunocastrated, steers, and heifers. Bulls had greater rib eye area and HCW (p = 0.0001). Heifers had increased fat thickness (p = 0.0001). Steers and heifers had higher marbling scores (p = 0.0001). There was interaction between gender and aging time for Warner‐Bratzler Shear Force (p = 0.0002), L* (p = 0.0118), and b* (p = 0.0113) values of beef. The sensory panel results showed that beef from bulls had the lowest consumer overall acceptance (p = 0.0278). Especially, regardless tenderness, steers and immunocastrated beef were considered tender, independent of aging time. Beef produced by heifers, steers, and immunocastrated is considered to be of higher quality than bulls. Thus, it is may be an interesting alternative to produce high‐quality beef than bulls, to attend the consumer demand for high‐quality products. Additionally, the low fatty acids n6 levels and low n6:n3 ratio, high levels of CLA, MUFAs, and oleic acid suggests that the heifer meat is favorable for human health.     

Correlation of properties of Brazilian Haplustalfs with magnetic susceptibility measurements

Magnetic susceptibility (χ, mass specific) is useful for easy indirect estimation of other soil properties at a low cost. The aim of this study was to assess the use of χ as measured with an analytical balance for predicting properties with a substantial influence on the management of Typic Haplustalfs in southern Brazil. To achieve this 48 topsoil samples were taken at the intersection points in a rectangular grid of 20 m × 20 m cells, with 38 of these used for calibration and 10 for validation in regression analyses. The obtained χ values were slightly higher than, and highly correlated (r = 0.970; P < 0.001) with those measured with a susceptibility meter. Highly significant (P < 0.001) correlations were also found between χ and other soil properties relevant to soil classification and management such as clay content (r = 0.68), cation exchange capacity (r = 0.62), P sorption capacity (r = 0.76) and haematite content (r = 0.82). Results from a principal component analysis of eight properties important for soil classification explained 11% of the variance in the data set. The good predictive ability of χ was consistent with current knowledge on the formation pathways for pedogenic ferrimagnets. In summary, χ, which can be readily measured with an analytical balance, has the potential for quantifying soil attributes and may therefore be used in pedotransfer functions.     

The effect of density in larval rearing of the pullet carpet shell Venerupis corrugata (Gmelin, 1791) in a recirculating aquaculture system

The pullet carpet shell Venerupis corrugata is an economically valuable species in several European countries, however, nowadays stocks are under high fishing pressure. Hatchery production of juveniles for release is a major contributor to strengthen the stock and consequently improve the sustainability of the natural stocks. This study aimed to determine the feasibility of rearing V. corrugata larvae with different larval densities (10, 40 and 200 larvae per mL) in a recirculating aquaculture system (RAS), compared with the traditional larval rearing methodology (Batch). The mean survival, growth and metamorphic rate of V. corrugata larvae in RAS was higher (11.1%; 71.3 μm; 21.6% respectively) than in the Batch system, in all tested densities. The larval growth was not affected by the initial density until 40 larvae per mL, however, 200 larvae per mL decreased the larval growth in length nearly 54 μm. The larval rearing time was shortened in 2 days in the RAS system. The physical, chemical and microbiologic parameters suggested that the tested densities were not excessive to disturb the biofilter stability of RAS. The V. corrugata larval rearing performed at high larval stocking densities in RAS system present a reduction in the operating costs to produce this species.     

New species in aquaculture: are the striped venus clam Chamelea gallina (Linnaeus, 1758) and the surf clam Spisula solida (Linnaeus 1758) potential candidates for diversification in shellfish aquaculture?

The surf Spisula solida and the striped venus Chamelea gallina clams support important fisheries in Europe. These fisheries have been affected by inter‐annual fluctuations in stock abundance and recruitment failures. Aquaculture could contribute to address these problems through the production of larvae or juveniles for stock‐enhancement programmes. In the present study, the prerequisites to produce these species in hatchery were established. Of the different methods used to obtain gametes (thermal stimulation, scarification and flow through), C. gallina spawned in the flow through only. By its turn, the best method for obtaining gametes for S. solida was stripping. Higher survivals of D‐larvae were found at 15 and 17°C. The greatest larval survival and growth rates were obtained from larvae fed Isochrysis aff. galbana (T‐iso). First C. gallina and S. solida pediveliger larvae were found at day 8 and day 26 respectively. The presence of metamorphosed larvae found even in the unfed treatment for C. gallina and for S. solida is an advantage for aquaculture production. After metamorphosis, the S. solida juveniles' survival was quite low, whereas there was no mortality for C. gallina juveniles reared without substrate regardless the diet provided. Juveniles fed the binary diet (Chaetoceros calcitrans ‐ C. cal + T.iso) and the monodiet T‐iso showed relatively higher growth in shell length and weight than C. cal. The hatchery production of these two species was possible, however the results of this study showed that C. gallina can be more attractive for aquaculture than S. solida.     

Acquired resistance of horses to Amblyomma cajennense (Fabricius, 1787) ticks

Acquired immunity of horses to larvae, nymphs and adults of the Amblyomma cajennense tick was evaluated through three consecutive experimental infestations of tick-bite na?ve hosts. Data from these infestations were compared to those from field-sensitized horses and donkeys. It was observed that tick-bite na?ve horses developed a low level of resistance after two infestations as shown by a significant decrease in larval yield and a tendency for lower engorged weight of nymphs during third infestation. Ticks fed on field-sensitized horses had a similar biological performance to that observed on the third infestation of tick-bite na?ve horses but the mean engorged nymph weight was significantly lower than that of the first infestation from tick-bite na?ve horses. Donkeys presented the strongest resistance with significantly lower engorged weights of all instars and of the egg mass compared to the first infestation of tick-bite na?ve horses. Donkeys also displayed a significantly higher resistance than field-sensitized horses as demonstrated by significantly lower egg mass weights. Overall these results indicate that donkeys but not horses maintain a strong resistance to A. cajennense ticks. The importance of these findings in relation to vectoring of tick-borne diseases is discussed.     

Hematology of free-living marsh deer (Blastocerus dichotomus) from southeast Brazil.

This work reports basic hematologic values of a sample of a population of free-living marsh deer (Blastocerus dichotomus) living by the Paraná River in Southeast Brazil. Hematologic values are presented separately for male, female, and young animals as well as for anesthetized and nonanesthetized cervids. Nonanesthetized deer restrained by physical means had significantly higher erythrocyte indices and total leukocyte counts. Comparisons of blood parameters of anesthetized animals of different ages and gender differed slightly, with only two significant differences observed: young animals had significantly higher red blood cell counts than adult males and a lower blood total protein content when compared to adult females. Results indicate that two main reference ranges for blood values should be considered for marsh deer, for blood obtained from anesthetized or physically restrained individuals.     

Three-dimensional structure of an oncogene protein: catalytic domain of human c-H-ras p21

The crystal structure at 2.7 A resolution of the normal human c-H-ras oncogene protein lacking a flexible carboxyl-terminal 18 residue reveals that the protein consists of a six-stranded beta sheet, four alpha helices, and nine connecting loops. Four loops are involved in interactions with bound guanosine diphosphate: one with the phosphates, another with the ribose, and two with the guanine base. Most of the transforming proteins (in vivo and in vitro) have single amino acid substitutions at one of a few key positions in three of these four loops plus one additional loop. The biological functions of the remaining five loops and other exposed regions are at present unknown. However, one loop corresponds to the binding site for a neutralizing monoclonal antibody and another to a putative "effector region"; mutations in the latter region do not alter guanine nucleotide binding or guanosine triphosphatase activity but they do reduce the transforming activity of activated proteins. The data provide a structural basis for understanding the known biochemical properties of normal as well as activated ras oncogene proteins and indicate additional regions in the molecule that may possibly participate in other cellular functions.     

Seminal plasma insulin-like growth factor I and total protein concentration in peripubertal period of the Gyr bulls

This study aimed to evaluate the correlation of seminal plasma IGF-I and total proteins from peripubertal bulls with semen characteristics and onset of puberty. Sixteen dairy Gyr bulls were separated into early (n = 8) and regular (n = 8) groups, according to the onset of puberty. Semen was monthly collected by electroejaculation from 14 to 26 months of age, and the onset of puberty was retrospectively determined (17.0 ± 1.6 and 19.2 ± 1.5 months, to early and regular group, respectively). Five time points were evaluated (day −60, day −30, day 0, day 30 and day 60 days of puberty), being day 0 considered as beginning of puberty. Scrotal circumference and body weight were also assessed. Semen characteristics were evaluated, the seminal plasma was separated by centrifugation and total protein and IGF-I concentrations were determined. There was no difference between groups to concentration of the seminal plasma total proteins, but we found an interaction between group and age. Seminal plasma IGF-I concentrations were not different between early and regular groups; thus, the data were combined for analysis. Combined IGF-I concentrations were positively correlated with sperm motility and concentration, age, body weight and scrotal circumference. Negative correlation was found between IGF-I concentration and total sperm defects. Increased IGF-I was observed in day −30 and day 0 of puberty in early and regular groups, respectively. Seminal plasma total proteins are involved in peripubertal modifications and IGF-I from Zebus dairy bulls can influence the seminal characteristics and the growth factor increase occurs concomitantly with body growth but cannot be used to define puberty bulls earlier.     

Phytoplankton succession in intensive marine shrimp culture ponds treated with a commercial bacterial product

Succession of phytoplankton dominance was studied in shrimp culture ponds treated with commercial bacterial products. Diatoms were dominant and the cyanobacteria were absent in both treated and control ponds at the beginning of the culture period. After 34 days, the diatoms significantly decreased whereas cyanobacteria increased in both ponds. Chlorophyll a increased from a mean of 35.56 mg m^?3 in the first phase to 186.00 mg m^?3 in the final phase, and from 42.12 mg m^?3 to 242.81 mg m^?3 in the treated and control ponds respectively. Cyanobacteria were significantly higher in the control compared with the treated ponds during the final phase of the culture. Algal bioassay showed that the addition of nitrogen either alone or with silica to pond water significantly increased the specific growth rate of Chaetoceros calcitrans. The specific growth rate of Oscillatoria sp. significantly increased when a combination of nitrogen, phosphorus and carbon was added to the pond water. Addition of silica seemed to depress the growth rate of Oscillatoria sp. Nutrient enrichment should be minimized and the supply of nitrogen and silica should be adequate for promoting the growth of beneficial phytoplankton in aquaculture systems.