Semen characteristics of Colossoma macropomum from three successive sample collections in the same reproductive cycle

The objective of this work was to evaluate the semen characteristics of C. macropomum fish from three successive semen sample collections taken during the same reproductive cycle. Six breeders (6.4 ± 1.5 kg) induced with crude carp pituitary extract (2.5 mg kg^?1) were used. Samples of semen were collected in graduated syringes after a period of 260 degree‐hours. The semen was collected from the same males in September 2014 (sample 1), December 2014 (64 days after the first collection – sample 2) and February 2015 (86 days after the second collection – sample 3). The semen volume was higher (P < 0.05) in the sample 1 (6.7 mL) and sample 2 (3.4 mL) than in the sample 3 (1.0 mL). Sperm concentration and normal sperm did not significantly differ between samples. Likewise, sperm motility, curvilinear velocity, displacement velocity, oscillation and beat cross frequency did not vary, whereas straight‐line velocity, straightness and progression were higher (P < 0.05) in sample 2 (December). In general, despite lower amounts, the semen appeared to be of good quality for all three samples collected during the same reproductive period.     

Does habitat fragmentation affect landscape-level temperatures? A global analysis

Landscape Ecology - Habitat fragmentation per se (habitat subdivision independent of habitat loss) is a major driver of biodiversity change, potentially due to its impacts on climate. Habitat...     

Effect of the Lactiplantibacillus plantarum and Lentilactobacillus buchneri on corn and sorghum silage quality and sheep energy partition under tropical conditions

This study aimed to evaluate the silage quality, ingestive behaviour, and sheep energy partition fed corn and sorghum silages, with or without inoculation with Lactiplantibacillus plantarum and Lentilactobacillus buchneri. Whole plants of one dent corn hybrid (DCS), one flint corn hybrid (FCS), and one forage sorghum hybrid (SS) were ensiled with or without an inoculant containing L. plantarum and L. buchneri (4 × 10⁵ CFU g⁻¹), totalling six treatments (3 × 2 factorial scheme). The treatments were ensiled in metal drums with 200 L capacity. The lactic acid concentrations in the inoculated FCS and DCS were higher by 13.4% and 12.8%, respectively, than those in the non-inoculated plants. In contrast, the lactic acid concentration in the inoculated SS was 23.1% lower than that in the non-inoculated SS. Furthermore, there were differences in pH and acetic acid concentrations only in SS, which were 2.3% and 45.2% higher, respectively, in inoculated silage than in non-inoculated silage. In inoculated DCS and SS, propionic acid concentrations were 1.7 times higher (for both silages), and 1-propanol was 3.7 and 1.8 times higher compared than those in non-inoculated silages. There was a main effect of the inoculant on 1,2-propanediol concentrations, which were 37.5% higher in inoculated silages than in non-inoculated silages. However, ingestive behaviour, heat and methane production, and silage net energy concentrations were not affected by inoculant use. Fermentative modifications caused by inoculation with L. plantarum and L. buchneri in whole plant corn or sorghum silage did not modify sheep energy partition.     

The use of native vegetation as a proxy for habitat may overestimate habitat availability in fragmented landscapes

Context

Native vegetation is often used as a proxy for habitat to estimate habitat availability in landscapes. This approach may lead to incorrect estimates of the impacts of habitat loss and fragmentation on species, which have not been thoroughly quantified so far.

Objectives

We quantified to what extent the loss of native vegetation reflect actual habitat loss by native species in landscapes. We tested the hypothesis that habitat availability declines at greater rates than native vegetation and thus is overestimated when it is quantified on the basis of native vegetation.

Methods

Using simulations, we quantified how the loss of native vegetation in artificial and real landscapes affects habitat availability for species with different habitat requirements. We contrasted a generalist species, which uses all native vegetation, with 10 habitat-specialist species classified into three categories (interior, patchy and riparian species).

Results

Habitat availability generally declined at greater rates than native vegetation for all specialist species. This pattern was apparent for different specialist species in a broad range of landscape types. Interior species always lost habitat availability more rapidly than the generalist species. Most riparian species lost habitat availability more rapidly than the generalist species. Responses of patchy species were more complex, depending on their dispersal abilities and landscape structure.

Conclusions

Habitat availability is likely to be overestimated when native vegetation is used as proxy for habitat, because habitat availability will generally decline at greater rates than native vegetation. Therefore, a species-centered approach should be adopted when estimating habitat availability in landscapes.

     

Hemodynamic responses of the caudal artery to toxic tall fescue in beef heifers

Color Doppler ultrasonography was used to compare blood flow characteristics in the caudal artery of heifers fed diets with endophyte (Neotyphodium coenophialum) infected (E+) or noninfected (E-) tall fescue seed. Eighteen crossbred (Angus x Brangus) heifers were assigned to 6 pens and were fed chopped alfalfa hay for 5 d and chopped alfalfa hay plus a concentrate that contained E-tall fescue seed for 9 d during an adjustment period. An 11-d experimental period followed, with animals in 3 pens fed chopped alfalfa hay plus a concentrate with E+ seed and those in the other 3 pens fed chopped hay plus concentrate with E E- seed. Color Doppler ultrasound measurements (caudal artery area, peak systolic velocity, end diastolic velocity, mean velocity, heart rate, stroke volume, and flow rate) and serum prolactin were monitored during the adjustment (baseline measures) and during the experimental period. Three baseline measures were collected on d 3, 5, and 6 during the adjustment period for comparison to post E+ seed exposure. Statistical analyses compared the proportionate differences between baseline and response at 4, 28, 52, 76, 100, 172, and 268 h from initial feeding of E+ seed. Serum prolactin concentrations on both diets were lower (P <0.001) than baseline beginning at 4 h from the start of the experimental period. However, trends in serum prolactin concentrations for heifers on the E- diet suggested ambient temperature was affecting these concentrations. Caudal artery area in E+ heifers had declined (P <0.10) from baseline by 4 h and was consistently lower (P <0.05) for the remainder of the period. Heart rates for E+ heifers were lower than the baseline rate from 4 (P <0.10) to 100 (P <0.001) h, but were similar (P >0.10) to the baseline for 172 and 268 h measures. Blood flow in E+ heifers was consistently lower than the baseline from 4 (P <0.05) to 172 (P <0.001) h, but was similar to the baseline at 268 h when heart rate was similar to the baseline rate. Caudal artery areas for the E- diet were similar to baseline areas except at 100 h when it was greater than baseline. Heart rates and flow rates for E- heifers did not differ (P >0.10) from baseline measures during the experimental period. Results indicated that onset of toxicosis was within 4 h of cattle exposure to E+ tall fescue and is related to vasoconstriction and reduction in heart rate.     

Forage and breed effects on behavior and temperament of pregnant beef heifers

Background： Integration of behavioral observations with traditional selection schemes may lead to enhanced animal well-being and more profitable forage-based cattle production systems.Brahman-influenced（BR;n = 64） and Gelbvieh × Angus（GA;n = 64） heifers consumed either toxic endophyte-infected tall fescue（E＋） or one of two nontoxic endophyte-infected tall fescue（NT） cultivars during two yr.Heifers were weighed at midpoint and termination of grazing.Grazing behavior（grazing,resting in the shade,lying,or standing without grazing） was recorded（n = 13 visual observations per yr in June and July） for each pasture.During yr 2,exit velocity（EV） and serum prolactin（PRL） were determined.Results： Grazing behavior was influenced（P 0.05） by an interaction between fescue cultivar and breed type.Gelbvieh × Angus heifers assigned to E＋ pastures had the lowest percentage of animals grazing and the largest percentage of animals resting in the shade.Brahman-influenced heifers had faster EV（P 0.001） than GA heifers（0.52 vs.0.74 ± 0.04 s/m,respectively）.Body weight（BW） was affected（P 0.01） by an interaction of tall fescue cultivar and d,and an interaction of tall fescue cultivar and breed type.Heifers grazing NT pastures were heavier（P 0.01） than heifers grazing E＋ pastures at midpoint and termination.Gelbvieh × Angus heifers grazing NT pastures were heavier（P 0.01） than GA and BR heifers grazing E＋ and BR heifers grazing NT pastures.An interaction of forage cultivar and breed type occurred on serum PRL（P 0.01）.Conclusion： Collectively fescue cultivar,EV,and concentrations of serum PRL were associated with grazing behavior.Heifers grazing NT pastures were observed to be grazing more than heifers assigned to E＋ pastures,regardless of breed type,which may have contributed to changes in BW and average daily gain（ADG） in heifers.Integration of behavioral observations along with traditional selection schemes may lead to enhanced animal well-being and more profitable forage-based cattle production systems.     

Epidermal growth factor receptor expression in feline oral squamous cell carcinomas

Feline oral squamous cell carcinomas (SCC) have a poor prognosis despite aggressive treatment with surgery, radiation and anticancer drugs. Overexpression of the epidermal growth factor receptor (EGFR), a membrane‐bound tyrosine kinase receptor, has been found in many human epithelial neoplasms, including oral SCC. EGFR overexpression has been associated with advanced disease and a poor prognosis. The purpose of this study was to determine whether feline oral SCC express EGFR. Thirteen formalin‐fixed paraffin wax‐embedded biopsy samples from feline oral SCC were analysed for EGFR expression using immunohistochemistry. Nine of 13 tumours (69%) were positive for EGFR expression, suggesting that altered EGFR expression plays a role in feline oral SCC and provides a rationale for a potential clinical benefit using EGFR inhibitors in combination with conventional treatments.     

The effects of the number,size and isolation of patches along a gradient of native vegetation cover: how can we increment habitat availability?

Habitat availability—or how much habitat species can reach at the landscape scale—depends primarily on the percentage of native cover. However, attributes of landscape configuration such as the number, size and isolation of habitat patches may have complementary effects on habitat availability, with implications for the management of landscapes. Here, we determined whether, and at which percentages of native cover, the number, size and isolation of patches contribute for habitat availability. We quantified habitat availability in 325 landscapes spread across the state of Rio de Janeiro, in the Atlantic Forest hotspot, with either high (>50 %), intermediate (50–30 %), low (30–10 %) or very low (<10 %) percentage of native cover, and for six hypothetical species differing in inter-patch dispersal ability. Above 50 % of native cover, the percentage of cover per se was the only determinant of habitat availability, but below 50 % the attributes of landscape configuration also contributed for habitat availability. The number of patches had a negative effect on habitat availability in landscapes with 50–10 % of native cover, whereas patch size had a positive effect in landscapes with <10 % of native cover. The different species generally responded to the same set of landscape attributes, although to different extents, potentially facilitating decision making for conservation. In landscapes with >50 % of native cover, conservation actions are probably sufficient to guarantee habitat availability, whereas in the remaining landscapes additional restoration efforts are needed, especially to reconnect and/or enlarge remaining habitat patches.     

Plantation rows as dispersal routes: A test with didelphid marsupials in the Atlantic Forest, Brazil

Anecdotal observations suggest that some vertebrates follow plantation rows when crossing between habitat patches in fragmented landscapes, but the frequency of such behavior was never formally tested despite its potential implications for landscape management. We experimentally tested if the didelphid marsupials Didelphis aurita and Philander frenatus use plantation rows as guidelines when searching for habitat patches in a landscape of fragmented Atlantic Forest in Brazil. Thirty-seven individuals of P. frenatus and 24 of D. aurita were captured in forest fragments and released carrying spool-and-line tracking devices at four distances (30-200 m) from a forest fragment, in a matrix of manioc plantations. Animals of both species used plantation rows to orient their initial movements and used rows as guidelines along their paths for navigating in the matrix. By moving predominantly parallel to the plantation rows animals reduced the tortuosity of their paths and obtained an unobstructed view of the landscape ahead. These results demonstrate that the orientation of linear plantations can strongly influence functional connectivity between habitat fragments. Plantation rows should be oriented to maximize connection between nearby fragments, enhancing dispersal success of these species and probably many other terrestrial vertebrates in agricultural landscapes.