Green tea flavan-3-ols and oligomeric proanthocyanidins inhibit the motility of infective larvae of Teladorsagia circumcincta and Trichostrongylus colubriformis in vitro

The effects of a hot water infusion and an aqueous acetone extract of green tea (Camellia sinensis) on the motility of infective larvae of the sheep nematodes Teladorsagia circumcincta and Trichostrongylus colubriformis were investigated under in vitro conditions. The infusion and extract dose-dependently inactivated the infective larvae as assessed by the larval migration inhibition (LMI) assay. To determine the components responsible for the inhibitory activity, the hot water infusion and aqueous acetone extract of green tea were fractionated on Sephadex LH-20 and the green tea extract fractions (GTE-I-VIII) characterised by mass spectrometry. The larvae were exposed to increasing concentrations of these GTE fractions. Fractions containing epigallocatechin gallate (EGCG) and proanthocyanidin oligomers were most effective. GTE fractions were more effective against T. circumcincta than T. colubriformis larvae as assessed by the LMI assay.     

Salmonella enteritidis clearance and immune responses in chickens following Salmonella vaccination and challenge

Our previous work showed that the cell-mediated immunity (CMI) was enhanced by live Salmonella vaccine (LV). The objective of this study was to evaluate the impact of live and killed Salmonella vaccines on Salmonella enteritidis (SE) clearance and to determine if the clearance was mediated by cell-mediated and/or humoral immunity. Chickens were first immunized at 2 weeks of age followed by a booster dose at 4 weeks, challenged with live SE 2 weeks later (6-week-old) and tested for CMI, antibody response and SE clearance 1-week post SE-challenge (7-week-old). Spleen cell proliferation induced by SE-flagella and Concanavalin A (Con A) were significantly higher and SE shedding was significantly lower in the LV group. The splenic CD3 population was significantly lower and B cells were higher in the control group compared to all the SE-challenged groups (with and without vaccination). Serum antibody to SE-flagella and envelope were significantly higher in the KV group compared to all the other groups. These results suggest that LV protects against SE infection, probably by enhancing the CMI.     

Frequency of the mutant MDR1 allele associated with multidrug sensitivity in a sample of collies from France

A study was performed to determine the frequency of the mutant MDR1 allele associated with ivermectin sensitivity in a sample of collies living in France. Buccal swab samples were collected from approximately 83 collies for determination of MDR1 genotype. DNA was extracted and the polymerase chain reaction was performed to amplify a 148 bp (wildtype MDR1 genotype) or 144 bp (mutant MDR1 genotype) amplicon containing the MDR1 mutation. Sequence analysis was performed to determine the genotype of each dog. Adequate quantities of DNA for unequivocal genotyping were obtained from only 25 of 83 swabs. Twenty percent (5/25) of the collies studied were homozygous for the normal allele (normal), 32% (8/25) were heterozygous (carrier), and 48% (12/25) were homozygous for the mutant allele (affected). The results of this study indicate that a high percentage of collies presenting to veterinarians in France harbor the MDR1 mutation, thus impacting some therapeutic decisions.     

Comparison of three methods of feeding sows in gestation and the subsequent effects on lactation performance

A total of 684 sows from breeding groups over 6 wk was used to compare three methods of feeding during gestation on gestation and lactation performance. Control gilts and sows were fed according to body condition based on a scale of 1 to 5 (1 = thin, 5 = fat). Sows were visually assessed for body condition at breeding and were assigned a daily feed allowance to achieve a BCS of 3 at farrowing. Treatment 2 used feeding levels based on backfat thickness (measured between d 0 and 5 after breeding) and weight at weaning for sows or service for gilts. Feed allowance was calculated to achieve a target backfat of 19 mm at farrowing, and remained constant from d 0 to 101 of gestation. Feed allowances were based on modeled calculations of energy and nutrient requirements to achieve target sow maternal weight and backfat gains. Treatment 3 was identical to Treatment 2, except that feeding pattern was altered for thin sows and gilts (<15 mm at service) in an attempt to reach 19 mm by d 36 of gestation. Sows were weighed at the previous weaning, and gilts were weighed at service, with both weighed again between d 112 and 114 of gestation. Backfat was measured between d 0 and 5, and again between d 108 and 113 of gestation. At farrowing, sows on Treatments 2 and 3 had 19 and 19.1 mm of backfat, respectively, whereas control sows tended to have greater (P < 0.07) backfat (20 mm). On average, sows targeted to gain 6 to 9 mm of backfat failed to reach target gains regardless of feeding method. Feeding sows in gestation based on backfat (Treatments 2 and 3) resulted in a numerically higher proportion of sows in the target backfat range of 17 to 21 mm (40.2, 53.3, and 52.6% for control and Treatments 2 and 3, respectively) at farrowing and a numerically lower percentage of fat sows (>21 mm), but no difference in the percentage of thin sows (<17 mm) compared with feeding based on body condition. In conjunction with this observation, sows fed based on BCS were fed higher (P < 0.05) feeding levels in gestation than were sows fed based on backfat depth. Gestation feeding method had no effect on performance during lactation. Feed intake in lactation was lower (P < 0.05) for high backfat sows (>21 mm) at farrowing compared with sows with <21 mm. The high proportion of sows in the optimal backfat category demonstrates that feeding based on backfat and BW has potential for facilitating more precise feeding during gestation.     

Risk Analysis of Antibiotic Resistance, Berlin, BfR, 10-12 November 2003: activities of the Codex Alimentarius Commission related to antibiotic resistance

The FAO/WHO Codex Alimentarius Commission develops recommendations concerning risk management related to regulatory issues, on the basis of scientific advice provided by FAO and WHO. The complex question of anti-microbial resistance that requires a multidisciplinary approach, has been considered from different point of views in the framework of Codex, especially food hygiene and veterinary drugs and to a lesser extent, plant protection. Antibiotic resistance was considered from the perspective of the food chain and a risk profile was developed. Risk management options were also considered and may be grouped in two main categories: prevention of contamination through the food chain; and prudent use of anti-microbials. It is recognized that further scientific advice is necessary before developing specific risk management options in the framework of Codex. It is expected that the results of the FAO/OIE/WHO Expert Consultations on anti-microbial resistance will provide the necessary guidance for further action.     

Effect of anionic salt and highly fermentable carbohydrate supplementations on urine pH and on experimentally induced hypocalcaemia in cows

The objective of this experiment was to determine the effect of dietary grain on calcium homeostasis. Six rumen-fistulated dairy cows with 3 or more previous lactations and no history of parturient paresis were randomly assigned to a sequence of diets in a crossover study with 4 periods of 10 days each. Dietary treatments were: A control ration consisting of wrap grass silage alone (1), the control ration supplemented with ammonium chloride and ammonium sulphate salt solution (2), control ration following a period with supplementation (3) and control ration supplemented with increasing amounts of barley from 4 to 10 kg/cow per day, expected to produce subclinical rumen acidosis (4). Daily intake of the diets was adjusted to 14 kg DM/cow per day. On day 11, the calcium-regulating mechanisms in cows were challenged until recumbency by a standardized intravenous EDTA infusion and cows were left to recover spontaneously. Anion supplementation and the feeding of highly fermentable carbohydrate lowered urine pH below 7.0 due to subclinical acidosis. During spontaneous recovery from EDTA induced hypocalcaemia, the cows more quickly regained a whole blood free calcium concentration of 1.00 mmol/L if they had most recently been supplemented with either anionic salts or with increasing amounts of barley, as compared to the basic ration. It is concluded that so-called slug-feeding or 'steaming up' with highly fermentable carbohydrates before parturition in milk fever susceptible cows enhanced calcium homeostasis similar to the effect seen in cows on anionic diets.     

Studies on immunocompetence status in two turkey varieties in India

(1) Two hundred and twenty-seven adult turkeys of both sexes, of two varieties (104 Black and 123 White) were used to evaluate their immunocompetence status and body weights. (2) Response to sheep red blood cells (SRBC) (humoral immunity) was measured by Haemagglutination (HA) test 5 days post immunisation (dpi) and expressed as log2 values. Mercaptoethanol resistant (MER) antibodies representing IgG were determined by Mercaptoethanol HA test and Mercaptoethanol sensitive (MES) antibodies, representing IgM as the difference in total HA titre and IgG. Serum lysozyme concentrations were estimated by 'Lysoplate assay' and expressed in log2 values. (3) Least squares analysis of variance revealed that the White variety had higher adult body weight (4.788 +/- 0.040 kg) than the Black (3.774 +/- 0.044 kg). Sexual dimorphism was apparent and meals were heavier than females in both varieties. The interaction effect of variety and sex on body weight was also significant. (4) Least squares means for immunological traits, namely, total anti-SRBC antibodies, MER, MES titres and serum lysozyme were 7.161 +/- 0.189, 0.801 +/- 0.071, 6.362 +/- 0.160 and 1.766 +/- 0.043 microg/ml, respectively. The Black variety had a higher MES antibody titre than the White. (5) Sex had an effect on all the immunological traits except on MER titres. Females generally had higher anti-SRBC, MER and MES titres and serum lysozyme. The variety x sex interaction effect was significant for MES titres and serum lysozyme. White males had the lowest MES titres.