Membrane-associated proteins of ejaculated sperm from Morada Nova rams

AbstractThe objective was to describe the profile of membrane proteins from sperm of tropically adapted Morada Nova rams (N = 5). Samples from protein-enriched fractions of ejaculated sperm (containing 400 μg of protein) were separated by two-dimensional electrophoresis and respective maps analyzed using PDQuest software (version 7.3.0; Bio-Rad). Proteins were identified using tandem mass spectrometry. Also, membrane proteins were incubated with antibodies against binder of sperm protein (BSP) 1 and bodhesin 2 (Bdh-2), components of vesicular gland secretion. For membrane proteins of ejaculated sperm, an average of 133 ± 4.6 spots were detected per gel, of which, 107 spots were consistently present on all gels. Sixty-eight spots and 37 proteins were identified using mass spectrometry, corresponding to 71.6% of the intensity of all spots detected. Three major spots identified as ram seminal vesicle protein (RSVP) 14 represented approximately 30% of the intensity of all spots. Two of the most intense spots in the gel reacted against anti-BSP1, at 14 kDa. In addition, four low molecular weight spots reacted with anti-Bdh-2 antibodies. Proteins RSVP and Bdh-2 belong to the BSP and spermadhesin families, respectively, and were previously reported as major components of ram seminal proteins. Additional proteins identified in the sperm membrane two-dimensional maps included alpha-2-heparan sulfate-glycoprotein, plasma glutamate carboxypeptidase, arylsulfatase A, cathelicidin, heat shock protein 70 kDa, angiotensin-converting enzyme, leucine aminopeptidase, and clusterin. Some proteins were present as multiple isoforms, such as tubulin (12), alpha-2-heparan sulfate-glycoprotein (5), ATP synthase (5), Bdh-2 (4) and RSVP14 (3). Based on gene ontology analysis, the most common biological processes associated with the membrane proteins were cellular processes (34%), response to stimulus (14%), and metabolic processes (11%). Binding (37%) and catalytic activity (32%) corresponded to the most frequent molecular functions for those proteins. In conclusion, we identified a diverse cohort of components of membrane proteins in ram sperm. Major proteins previously reported in seminal plasma, such as RSVP14 and Bdh-2, were also extracted from sperm membranes. Knowledge of sperm proteins is crucial for elucidating mechanisms underlying their association with sperm function

Sward structure and livestock performance in guinea grass cv: Tanzania pastures managed by rotational stocking strategies

Grazing strategy is a key element in the determination of sward structure, herbage nutritive value and animal performance. We aimed to compare the herbage characteristics and performance of livestock in pastures of Panicum maximum cv. Tanzania managed, using two rotational stocking strategies, which provided either a fixed-length rest period (FRP) of 35 days in the spring and fall and 30 days in the summer, or a variable-length rest period (VRP), determined by the time required for the canopy to achieve 70 cm in height. The pastures were evaluated in the pregrazing condition for forage mass (FM); leaf (LP), stem (SP) and dead matter (DP) percentages; and nutritive value (NV). The animals were weighed every 28 days. Pastures managed with the FRPs exhibited greater FMs, SPs and DPs and lower LPs and NVs than those managed with the VRPs. The average daily livestock weight gain was greater during the spring and summer for the VRP than for the FRP pastures, resulting in an average animal weight gain per area of 990 and 860 kg ha−¹ wet period−¹ for the pastures managed with the VRPs and FRPs, respectively. Thus, pasture rest periods that were maintained after the sward reached 70 cm in height reduced the animal performance on Tanzania guinea grass