Inhibition of hemoglobin- and iron-promoted oxidation in fish microsomes by natural phenolics

Natural phenolic antioxidants have been tested in hake (Merluccious merluccious) microsomes as inhibitors of lipid oxidation promoted by fish muscle prooxidants: hemoglobin (Hb), enzymatic NADH-iron and nonenzymatic ascorbate-iron. The phenolics selected were as follows: (a) a grape phenolic extract (OW), (b) a fraction (IV) with isolated grape procyanidins with a medium-low degree of polymerization and galloylation percentage, (c) hydroxytyrosol obtained from olive oil byproducts, and (d) a synthetic phenolic antioxidant, propyl gallate. All compounds delayed lipid oxidation activated by Hb, enzymatic NADH-iron, and nonenzymatic ascorbate-iron, excluding hydroxytyrosol that was not an effective antioxidant on oxidation promoted by nonenzymatic iron. The relative antioxidant efficiency was independent of the prooxidant system, IV > propyl gallate > OW > hydroxytyrosol, and showed a positive correlation with their incorporation into microsomes (p < 0.05). The reducing capacity or ability for donating electrons and the chelating properties may also contribute to the antioxidant activity of phenolics, although these factors were less decisive than their affinity for incorporating into the microsomes. Conversely, the inhibition of Hb oxidation by phenolics and their polarity did not seem to play an important role on antioxidant mechanism. These results stressed the importance of incorporating the exogenous antioxidants into the membranes where are located key substances for fish lipid oxidation (highly unsaturated phospholipids, iron-reducing enzymes, and endogenous alpha-tocopherol).     

Hemodynamic effects of methylprednisolone acetate administration in cats

OBJECTIVE: To investigate the mechanisms by which corticosteroid administration may predispose cats to congestive heart failure (CHF). ANIMALS: 12 cats receiving methylprednisolone acetate (MPA) for the treatment of dermatologic disorders. PROCEDURE: The study was conducted as a repeated-measures design. Various baseline variables were measured, after which MPA (5 mg/kg, IM) was administered. The same variables were then measured at 3 to 6 days and at 16 to 24 days after MPA administration. Evaluations included physical examination, systolic blood pressure measurement, hematologic analysis, serum biochemical analysis, thoracic radiography, echocardiography, and total body water and plasma volume determination. RESULTS: MPA resulted in a substantial increase in serum glucose concentration at 3 to 6 days after administration. Concurrently, RBC count, Hct, and hemoglobin concentration as well as serum concentrations of the major extracellular electrolytes, sodium and chloride, decreased. Plasma volume increased by 13.4% (> 40% in 3 cats), whereas total body water and body weight slightly decreased. All variables returned to baseline by 16 to 24 days after MPA administration. CONCLUSIONS AND CLINICAL RELEVANCE: These data suggest that MPA administration in cats causes plasma volume expansion as a result of an intra to extracellular fluid shift secondary to glucocorticoid-mediated extracellular hyperglycemia. This mechanism is analogous to the plasma volume expansion that accompanies uncontrolled diabetes mellitus in humans. Any cardiovascular disorders that impair the normal compensatory mechanisms for increased plasma volume may predispose cats to CHF following MPA administration.     

Differential induction of pathogenesis-related proteins in banana in response to Mycosphaerella fijiensis infection

Black leaf streak or “black Sigatoka” is one of the most important diseases affecting bananas and plantains worldwide. Very few studies have been published on the host-pathogen interaction of this pathosystem, particularly at the molecular level. The aim of this work was to analyze, under controlled conditions, the enzyme activity of peroxidase (POX), phenylalanine ammonia lyase (PAL), β-1, 3-glucanase (GLU) and chitinase (CHI) as well as the production of H₂O₂ in banana plants infected with Mycosphaerella fijiensis. Defence responses were examined and compared in a resistant (Calcutta 4) and a susceptible (Williams) cultivar. Plants were inoculated and tested for enzyme activity at 0, 6, 12, 18, 24, 48 and 72?h after infection (HAI) and 6, 9, 12, 15 and 18?days after inoculation (DAI). A rapid induction of PAL, POX and GLU was observed in the resistant cultivar at 6–18 HAI as well as H₂O₂ production at 72 HAI. In contrast, in the susceptible cultivar, induction of these enzymes was only observed from 6 DAI. These results suggest that the first 72 HAI are important in determining the response of the host to the disease. Further studies characterizing banana responses to M. fijiensis at the early stages of the infection are necessary in order to better understand this host-pathogen interaction.     

Increasing energy and lysine in diets for growing-finishing pigs in hot environmental conditions: consequences on performance, digestibility, slurry composition, and gas emission

The influence of dietary nutrient concentration on growth performance, manure composition, and gas emission was studied in pigs in hot environmental conditions. A total of 64 intact males and 64 females [(Landrace × Large White) × Pietrain] weighing 63.1 ± 9.7 kg were divided into 2 dietary treatments: high (HD: 14.39 MJ of DE/kg and 1.11% Lys) and low (LD: 13.97 MJ of DE/kg and 1.01% Lys) in energy and Lys contents. Pigs were allocated to 32 split-sex pens with 4 pigs/pen and 16 pens/treatment. Average productive performance was recorded for 41 d (phase 1). After phase 1, 12 females of 103.3 ± 3.15 kg (6 per treatment) were selected and housed individually, and feces and slurry were collected during 3 and 4 consecutive days, respectively, to calculate nutrient digestibility and measure gas emissions (phase 2). For gas emission measurements, slurry was pooled by treatment and stored for 76 d. Initial composition of slurry and pH were analyzed. Maximum and minimum temperatures registered in the barn throughout the growing period were 35.1 and 18.1°C, respectively. Animals fed the HD diet grew more efficiently than pigs fed the LD diet (G:F, 0.43 vs. 0.40; SEM = 0.01; P < 0.05). Fat digestibility was greater in HD compared with LD pigs (88.0 vs. 84.9%; SEM = 0.9; P < 0.05). Slurry from pigs fed the LD diet showed greater DM, OM, total N, and VFA contents than slurry from pigs fed the HD diet. Cumulative NH(3), CO(2), and especially CH(4) emissions were greater in the HD slurry compared with the LD slurry (192.4 vs. 210.g of NH(3)/m(3); 2,712 vs. 3,210 g of CO(2)/m(3); 1,502 vs. 2,647 mL of CH(4)/kg of OM). Increasing feed density in the present study led to a more efficient growth, a decreased nutrient concentration in the slurry, and a greater gas emission.     

Ovarian activity in F1 prepubertal ewe lambs under tropical conditions

Seventy crossbred ewe lambs, born from Pelibuey (PB) dams mated with five sire breeds: White Dorper × PB (WD × PB), Black Head Dorper × PB (BHD × PB), Ile de France × PB (Ile × PB) Katahdin × PB (KT × PB) and Pelibuey (PB × PB), were used to determine age and weight to puberty, follicular populations during prepubertal development, ovulation rate at first ovulation and function of the first corpus luteum (FCL). Ewe lambs were maintained under grazing conditions and were supplemented with 300 g head^− 1 day^− 1 of a concentrate with 14% CP and 3.0 Mcal ME kg^− 1 of DM. From 145 days of age, monthly observations were performed by endoscopy to monitor follicular populations and luteal structures. Ovarian follicles were classified according to size into small (≥ 1 and < 3 mm), medium (≥ 3 and ≤ 4 mm) and large (> 4 mm). Additionally, weekly observations by ultrasonography were performed in four ewes per genotype to assess follicular populations. Luteal function from first ovulation was determined by circulating concentrations of progesterone. Ovulation rate was not affected by genotype (P > 0.05). All breed groups had the same pattern of follicular populations, where most of follicles were small, followed by medium and a small proportion of large follicles. Maximum diameter of follicles was similar for all genotypes during prepubertal development (P > 0.05), with an average range of 3.9 ± 0.20 to 4.4 ± 0.20 mm. The BHD × PB reached puberty at the youngest age of 240.9 ± 13.0 days, compared to all other genotypes (P < 0.05), 259.1 ± 11.7 for WD × PB, 279.3 ± 9.6 for KT × PB and 289.0 ± 15.3 days for PB × PB and 308.6 ± 11.9 days for Ile × PB ewe lambs. Ile × PB had greater weight to first ovulation (31.5 ± 1.19 kg) as compared to other breed groups (P < 0.01). The largest percentage of FCL was for KT × PB ewes (100%) (P < 0.05), followed by BHD × PB (88.9%), PB × PB (83.3), WD × PB (78.6%) and Ile × PB (77.8%). There were no differences in ovulation rate attributable to type of lambing from which ewe lambs came from (P > 0.05). BHD × PB ewe lambs reached puberty at an earlier age than other in this study. KT × PB ewe lambs had the highest percentage of FCL in their first ovulation. Breed of sire Ile de France increased weight to puberty and decreased FCL at first ovulation. In conclusion, the BHD × PB ewe showed puberty at an earlier age than other genotypes, while the KT × PB had the highest percentage of functional corpus luteum in their first ovulation. Ewe lambs coming from single lambings reach puberty at a heavier weight than those coming from multiple lambings. The ovulation rate in the first ovulation of ewe lambs is not affected by genotype and type of lambing.     

Characterization of the nutritive value of tropical legume grains as alternative ingredients for small‐scale pork producers using in vitro enzymatic hydrolysis and fermentation*

In the tropic, the small‐scale pork production is negatively influenced by the low availability of high protein ingredients. The study aimed to compare the protein and starch hydrolysis as well as fibre fermentation of five tropical legume grains (Canavalia brasiliensis, CB; Lablab purpureus, LP; Vigna unguiculata, white WVU; pink PVU and red RVU) and a control (extruded full‐fat soybean (SB)), using an in vitro model that simulated digestion in the gastrointestinal tract of pigs. A sequential in vitro hydrolysis was carried out with pepsin (120 min) and pancreatin (240 min) to determine the degree of hydrolysis (DH) of protein and starch. The indigestible residue was fermented in vitro with pig faecal inoculum to compare the modelled kinetics of gas production over 72 h and the production of short‐chain fatty acids (SCFA). After 360 min of pepsin–pancreatin hydrolysis, SB and WVU had the highest protein hydrolysis (76% and 66%) and PVU and WVU the highest starch hydrolysis (70% and 64%) (p < 0.01). The in vitro fermentation of the indigestible residue of WVU resulted in the highest (482 ml/g DM; p < 0.001) and CB the lowest (335 ml/g DM) gas production. These data were consistent with the SCFA production. Butyrate, propionate and total SCFA were higher (or tended) for RVU and WVU when compared with CB and SB (p = 0.015–0.085). In conclusion, the high DH of protein and starch as well as the high gas and SCFA production obtained with raw WVU makes it an interesting alternative to SB as a feedstuff for swine nutrition in the tropic. Other legume grains (LP and CB) cannot be used by pigs in their raw form.