Effect of dietary xylitol on growth and inflammatory responses in immune stimulated chickens

It has been argued that stimulation of the immune system depresses performance. Accordingly, an experiment was conducted to determine the effect of dietary xylitol (150 g/kg diet) on growth and selected inflammatory responses in male broiler chickens. During the final 6 d of the experimental periods, chicks were injected with antigens: Escherichia coli lipopolysaccharide (LPS) on days 1, 3 and 5 and with Sephadex-G50 superfine on days 2 and 4 to stimulate macrophage functions. The immune stimulation reduced body weight gain and food intake, but enhanced alpha 1 acid glycoprotein (AGP) concentration and interleukin (IL-1) like activity in plasma. Feeding the xylitol diet partially, but significantly, prevented the reductions in body weight gain and food intake, without affecting the early stage of inflammatory responses triggered by LPS and Sephadex injections.     

Evidence of Damage in Cryopreserved and Fresh Bovine Embryos Using the Tunel Technique

The objective of the present study was to evaluate the quality of bovine embryos cryopreserved in different years in Chiapas, Mexico. The embryos were obtained from a government institution (FIMEGEN) dedicated to promoting embryo transfer among dual-purpose cattle farmers. Forty-three embryos frozen in 1988, 1989, 2000 and 2002 were analysed with the Tunel technique to detect programmed cell death (apoptosis). Eleven fresh embryos were used as controls. Analysis of variance was used in embryos stored in the different years with averages tested using Tukey's test. Student's t-test was employed to compare fresh and frozen cells. Embryos with shorter storage time presented a lower number (p < 0.001) of Tunel-positive cells compared with embryos stored for longer time. On the contrary, when comparing the number of apoptotic cells between frozen and fresh embryos a higher number of positive cells (p < 0.05) were found in the former. The present results suggest that the cryopreservation per se caused damage that compromises the viability of the embryo. Another explanation for the lower pregnancy rate found in the tropics could be irreversible damage caused by poor storage technique in these large operations.     

Effects of Prolonged Exposure to Low‐Dose Fumonisin B1 in Pigs

From the point of view of human exposure, fumonisins (FB₁, FB₂, FB₃, FB₄), a relatively recently (1988) discovered and identified group of mycotoxins, represent one of the five most important mycotoxin groups causing human disease. In an earlier experiment studying the effects of relatively low doses (10, 20 and 40 p.p.m.) of FB₁ in weaned piglets, it was established that the 4‐week feeding of 10 p.p.m. (mg/kg feed) FB₁ produced mild pulmonary oedema. This suggested the importance of studies with even lower doses of the toxin to determine the tolerable limits. The objective of this experiment was therefore to study the effects of prolonged (8‐week) exposure to still lower concentrations (0, 1, 5 and 10 mg/kg feed) of FB₁. The 8‐week feeding of FB₁ in low concentrations (1–10 p.p.m.) did not cause clinical signs and significant performance impairment in pigs, but rendered irreversible the chronic changes that had already developed in the animals in a dose‐dependent manner. Dissection revealed pathological alterations of the lungs in one of the animals given 1 p.p.m. (n=4), in two animals exposed to 5 p.p.m. (n=5), and in three animals given 10 p.p.m. (n=4). In all three treatment groups, proliferation of the connective tissue fibres, primarily of those around the lymphatic vessels, in the subpleural and interlobular connective tissue of the lungs, extending to the peribronchial and peribronchiolar areas, was seen. The results of this experiment call attention to the risk of prolonged low‐dose toxin exposure, which has very important public health implications.     

Experimental Leptospira borgpetersenii serovar hardjo infection of pregnant cattle

Objective To observe the effect upon the foetus of experimental infection of pregnant cattle with Leptospira borg-petersenii serovar hardjo .
Design A disease transmission study using pregnant cattle.
Procedure Fourteen heifers serologically negative to L hardjo were artificially inseminated and later challenged with a north-Queensland isolate of L hardjo by conjunctival inoculation. The heifers were serologically monitored and their urine examined for the presence of leptospires using culture and fluorescent-antibody tests at appropriate intervals. Elective caesarean sections were performed on pregnant heifers at 6.5 weeks after the challenge. Foetuses were examined using serological, histopathological, microbiological and fluorescent-antibody tests.
Results Ten of the heifers became pregnant, but three subsequently aborted before challenge. After challenge, all 14 heifers seroconverted and L hardjo was isolated from the urine of 6 of the 7 pregnant heifers. No evidence of foetal L hardjo infection was detected. Two of the foetuses had histopatho-logical lesions consistent with Neospora s p infection.
Conclusion It is likely that the isolate of L hardjo used in this study does not normally infect the foetus. Neospora s p may be a more significant cause of bovine reproductive wastage.     

Identification and antiradical properties of anthocyanins in fruits of Viburnum dilatatum thunb

The fruit of Viburnum dilatatum Thunb., called gamazumi, has been shown to prevent oxidative injury in rats given gamazumi crude extract (GCE). Therefore, phenolic compounds in GCE were purified by Sephadex LH-20 column chromatography and preparative high-performance liquid chromatography. Two major anthocyanins were isolated, and their structures were determined by NMR, liquid chromatography/electrospray ionization mass spectrometry/MS and sugar analysis as cyanidin 3-O-(2-O-beta-D-xylopyranosyl)-beta-D-glucopyranoside, namely, cyanidin 3-sambubioside (I) and that of cyanidin 3-O-beta-D-glucopyranoside, namely, kuromanin (II). This is the first identification of these compounds in V. dilatatum fruits, which contain I and II at 141.3 and 4.5 microg/g of fresh fruit, respectively. By the electron spin resonance method, the superoxide anion radical scavenging activities (IC(50)) of I and II were 17.3 and 69.6 microM, and their activities on hydroxyl radicals were 4.3 and 53.2 mM. As a positive control, the activities of ascorbic acid were 74.2 microM on superoxide anion radicals and 3.0 mM on hydroxyl radicals. Our results suggest that these anthocyanins having radical scavenging properties may be key compounds contributing to the antioxidant activity and physiological effects of V. dilatatum fruits.     

Evaluation of an Artificial Insemination Programme in a Seasonal Breeding Dairy System through Milk Progesterone

In order to evaluate an artificial insemination programme and reproductive efficiency of dairy herds in Uruguay, a survey was conducted with five dairy farms, utilizing a total of 768 lactating Holstein cows. Precision of oestrous detection was assessed by one milk progesterone sample taken on day of breeding and was 11.1%. Two additional samples taken at day 10 and 23 were used to confirm ovulation and early pregnancy. Accuracy of pregnancy estimation by milk progesterone was 70.4%. Reproductive efficiency was determined by the analysis of records. Average intervals from calving to first service were 101 days and to conception 132 days and these were affected by parity, body weight and body condition at calving, but not at breeding, or by milk production. Oestrous detection rates and pregnancy rates were 37.5 and 15.6%, respectively. It was concluded that losses in reproductive efficiency in dairy farms of Uruguay in a seasonal artificial insemination programme were mainly due to unobserved heats, rather than incorrect oestrous detection.