Can Microfiltered Seminal Plasma Preserve the Morphofunctional Characteristics of Porcine Spermatozoa in the Absence of Antibiotics? A Preliminary Study

Artificial insemination is extensively performed in pig farms in Europe, the United States and Canada. Antibiotics are typically added to the inseminating dose to limit bacterial growth during liquid phase storage at 16°C, as bacterial contamination is unavoidable. The World Organization for Animal Health (OIE) and the Food and Agriculture Organization (FAO) take action to control and reduce antibiotic use in animals as more bacteria are becoming resistant to antimicrobials. To avoid the use of antibiotics, we prepared inseminating doses using microfiltered seminal plasma (SP). Microfiltration is a common technology used to reduce bacterial contamination but may retain seminal substances, influencing sperm quality during storage. Therefore, the aim of this study was to evaluate the morphofunctional parameters of spermatozoa during storage at 16°C in doses prepared with or without microfiltered SP, with or without the addition of antibiotics, in a Latin square design. Artificial insemination doses with microfiltered SP and without antibiotic addition preserved spermatozoa viability, mitochondrial membrane potential, acrosome integrity and objective motility, with absolute values equal or even better than those observed in conventional doses. In conclusion, although the results could be considered preliminary due to the small sample size, this study suggests that microfiltration of SP can be a simple method, feasible on farms, to replace antibiotic use in extended doses stored in the liquid phase at 16°C for up to 7 days.     

The effect of veterinary-treated clinical mastitis and pregnancy status on culling in Swedish dairy cows

The interaction of the effects of pregnancy status and veterinary-treated clinical mastitis on culling in Swedish dairy cattle was analyzed with survival analysis. The data were from 978,780 cows with first calvings between 1988 and 1996. Four breeds (Swedish Red and White (SRB), Swedish Friesian (SLB), Swedish Polled Breed and Jersey) were included in the analysis, together with the SRB x SLB crossbreds. Length of productive life was defined as the number of days between first calving and culling or censoring (end of data collection). The model (Weibull proportional hazard) included the interaction of parity by pregnancy status by veterinary-treated clinical mastitis, peak test-day milk-yield deviation within herd-year-parity, age at first calving, year by season, region, breed, herd production level, and the random effect of herd. The effects of pregnancy status and veterinary-treated clinical mastitis were modeled as time-dependent covariates. The lactation was divided into five stages during which a veterinary-treated clinical mastitis and culling might occur and in which the pregnancy status was assumed to be known and culling could occur. Open cows had a pronounced effect on culling: they had a very high risk of being culled in all lactations, and it was even higher if they were treated for mastitis in early lactation. For pregnant cows, the later they got pregnant during the lactation, the greater their risk to be culled. The risk associated with cases of veterinary-treated clinical mastitis remained important throughout the lactation.     

Purification and characterization of a lipoxygenase enzyme from durum wheat semolina.

Purification of a lipoxygenase enzyme from the cultivar Tresor of durum wheat semolina (Triticum turgidum var. durum Desf) was reinvestigated furnishing a new procedure. The 895-fold purified homogeneous enzyme showed a monomeric structure with a molecular mass of 95 +/- 5 kDa. Among the substrates tested, linoleic acid showed the highest k(cat)/K(m) value; a beta-carotene bleaching activity was also detected. The enzyme optimal activity was at pH 6. 8 on linoleic acid as substrate and at pH 5.2 for the bleaching activity on beta-carotene, both assayed at 25 degrees C. The dependence of lipoxygenase activity on temperature showed a maximum at 40 degrees C for linoleic acid and at 60 degrees C for bleaching activity on beta-carotene. The amino acid composition showed the presence of only one tryptophan residue per monomer. Far-UV circular dichroism studies carried out at 25 degrees C in acidic, neutral, and basic regions revealed that the protein possesses a secondary structure content with a high percentage of alpha- and beta-structures. Near-UV circular dichroism, at 25 degrees C and at the same pH values, pointed out a strong perturbation of the tertiary structure in the acidic and basic regions compared to the neutral pH condition. Moreover, far-UV CD spectra studying the effects of the temperature on alpha-helix content revealed that the melting point of the alpha-helix is at 60 degrees C at pH 5.0, whereas it was at 50 degrees C at pH 6.8 and 9.0. The NH(2)-terminal sequence allowed a homology comparison with other lipoxygenase sequences from mammalian and vegetable sources.     

Colorimetric Analysis of <Emphasis Type="Italic">Hibiscus</Emphasis> Beverages and their Potential Antioxidant Properties

In food industry, roselle beverages and their subproducts could be functional ingredients since they are an excellent source of bioactive compounds with improved performance due to their important anthocyanins content. The aim of this study was to analyze anthocyanin content and antioxidant properties of aqueous infusions elaborated with color contrasting Hibiscus materials and design a mathematical model in order to predict color-composition relationship. Color measurements of beverages from roselle (Negra, Sudan and Rosa) were made by transmission spectrophotometry, anthocyanins quantification was determined by HPLC, and antioxidant potential was evaluated by in vitro methods (ABTS and FRAP assays). Beverages prepared with particle size minor of 250 μm presented until 4- and 2- times more anthocyanins content and antioxidant capacity respectively, in comparison to beverages prepared with powders with particle size major of 750 μm. Positive correlations among pigments composition and color parameters were found (p?<?0.05), showing that anthocyanins content, antioxidant capacity, C*_ab and h_ab values increased in relation with the smallest particle size of flours. Also, mathematical models were stablished to predict anthocyanin content (r?≥?0.97) and antioxidant capacity (r?≥?0.89) from color data; we propose equations for quick estimation of the antioxidant capacity in the Hibiscus beverages with high anthocyanin content. The obtained models could be an important tool to be used in food industry for pigment characterization or functional compounds with potential health benefits.     

Net requirements of calcium, magnesium, sodium, phosphorus, and potassium for growth of Nellore × Red Angus bulls, steers, and heifers

A comparative slaughter trial was conducted to assess the net requirements for gain of Ca, P, Na, K and Mg of bulls, steers and heifers of Nellore and Red Angus crossbreds. Twenty seven F1 Nellore and Red Angus crossbred calves (9 steers, 9 bulls, and 9 heifers), averaging 274 kg BW, were used. At the beginning of the trial, three animals from each gender were slaughtered to determine the initial body composition. The remaining 18 animals (3 animals of each gender) were randomly assigned to two treatments: fed 0.75 or 1.5% of BW of concentrate. The diets were based on corn silage and were isonitrogenous (2% N, DM). After three growing periods of 28 d, all animals were slaughtered. The cleaned gastrointestinal tract, organs, carcass, head, hide, tail, feet, and tissues were weighed to determine the empty BW (EBW). These parts were ground separately and subsampled for chemical analyses. The log of the contents of each mineral in the empty body was regressed on the log of the EBW to estimate the net requirement for each mineral per kg of empty body gain (EBG). There were no differences (P > 0.05) in the net requirements for growth of all macrominerals among genders. The equations of the pooled data of the net requirements for growth (g/kg EBG) were: 332.6 × EBW ^− 0.6367 for Ca, 112.1 × EBW ^− 0.5615 for P, 10.85 × EBW ^− 0.3992 for Na, 4.01 × EBW ^− 0.153 for K, and 3.589 × EBW ^− 0.462 for Mg. Our findings indicated that retained Ca and retained P were poorly related to the retained protein.     

Short-Term Dinoflagellate Bloom in a Shrimp Pond in Bahía de La Paz,Gulf of California

From mid-August to mid-September 1998, a dinoflagellate bloom in a shrimp pond near La Paz, Baja California Sur, was studied. Daily samples were taken of phytoplankton, dissolved oxygen, nutrient concentrations, photosynthetic pigments and proteins. The bloom occurred at temperatures of 29.7 to 33.2?°C. High densities of a Scrippsiella-like dinoflagellate (15.9?×?10⁶ cells/L) occurred on the first day of sampling, reaching a peak of 249?×?10⁶ cells/L on Day 13, and declining to 4 to 7?×?10⁶ cells/L by Day 26. Chlorophyll a varied from 8.63 mg/m³ on Day 4 to 141.38 mg/m³ on Day 13. Total nitrogen varied widely (0.2–11.50 μM) while phosphates peaked only once on Day 13 (4.14 μM). Proteins ranged from 523 to 6387 μg/L; the latter value occurred two days after the maximal peak of nitrates and coinciding with the highest level of phosphates. Fertilizers added to the ponds increased nutrient concentration and stimulated phytoplankton growth. In turn, the food supply to cultured shrimp noticeably increased throughout the bloom.