Immunolocalization of angiogenic growth factors in the ovine uterus during the oestrus cycle and in response to Steroids

The vascular changes associated with endometrial maturation in preparation for embryo implantation depend on numerous growth factors, known to regulate key angiogenic events. Primarily, the vascular endothelial growth factor (VEGF) family promotes vascular growth, whilst the angiopoietins maintain blood vessel integrity. The aim was to analyse protein levels of VEGFA ligand and receptors, Angiopoietin‐1 and 2 (ANG1/2) and endothelial cell receptor tyrosine kinase (TIE‐2) in the ovine endometrium in the follicular and luteal phases of the oestrus cycle and in response to ovarian steroids. VEGFA and its receptors were localized in both vascular cells and non‐vascular epithelium (glandular and luminal epithelium) and stroma cells. VEGFA and VEGFR2 proteins were elevated in vascular cells in follicular phase endometrium, compared to luteal phase, most significantly in response to oestradiol. VEGFR1 was expressed by epithelial cells and endothelial cells and was stimulated in response to oestradiol. In contrast, Ang‐1 and Ang‐2 proteins were elevated in luteal phase endometrium compared to follicular phase, and in response to progesterone, evident in vascular smooth muscle cells and glands which surround TIE‐2‐expressing blood vessels. Our findings indicate that VEGFA is stimulated by oestradiol, most predominantly in follicular phase endometrium, and Ang‐1 and 2 are stimulated by progesterone and were increased during the luteal phase of the oestrus cycle, during the time of vascular maturation.     

Paratuberculosis: A surgical method of diagnosis in practice

Summary

This article examines the use of the surgical mesenteric lymph node biopsy in cattle under field conditions. The surgical method and the complications which occurred are described. It is better not to give a sedative to an animal in advanced pregnancy. The site of the incision depended on the stage of pregnancy. In animals in advanced pregnancy the incision should be caudo‐ventral in the right‐hand flank. To prevent complications, the grid incision should be used then.     

The intravenous administration of johnin in the diagnosis of paratuberculosis in practice

Summary

The diagnostic value of the intravenous injection of 1.6 or 3.2 ml of johnin was evaluated in a total of 116 cattle. The sensitivity was 84% with clinically suspect cattle. A general reaction occurred frequently as well as elevation of body temperature (average 1.47° C). The observance of a general reaction was a good additional source of information when evaluating the test.

There was no significant difference in elevation of temperature between the cattle injected with 1.6 ml and those injected with 3.2 ml. A combination of diagnostic techniques such as the complement fixation test, intravenous johnin test, microscopic examination of the faeces and a biopsy examination of the rectal mucosa were necessary, in order to confirm the diagnosis of Johne's disease. In this manner a diagnosis can he confirmed with clinically suspect cattle in 96% of the cases.

The sensitivity of the intravenous johnin test was considerably lower in cases of non‐clinical Johne's disease.     

Detection and isolation of Toxoplasma gondii from fresh semen of naturally infected dogs in Southern Brazil

The aim of this study was to isolate Toxoplasma gondii and determine the viability of the parasite in fresh semen samples of clinically healthy adult dogs naturally infected. Eleven seropositive dogs with T. gondii IgG antibodies from southern Brazil were selected to confirm the presence and viability of T. gondii in fresh semen samples using in vitro isolation in Vero cell culture, polymerase chain reaction (PCR) and sequencing analysis. The presence of viable T. gondii was confirmed by in vitro isolation and PCR in five semen samples. The ITS1 region of the isolated protozoa (TG S4) was amplified and sequenced. The nucleotide sequence obtained was 99% compatible with the T. gondii DNA sequences stored in the GenBank. It has been shown that T. gondii tachyzoites may be isolated in vitro from fresh semen samples of clinically healthy dogs seropositive for T. gondii.     

Invited review: Amino acid bioavailability and digestibility in pig feed ingredients: terminology and application

In this review, the terminology that is used to describe the bioavailability and ileal digestibility of AA in pig feed ingredients is defined. Aspects of the methodology to establish bioavailability and ileal digestibility values also are discussed, and recommendations about the use of these values are provided. Two main factors can contribute to differences between bioavailability and ileal digestibility of AA. First, some AA, such as Lys, may be absorbed in chemical complexes that preclude their use for metabolism. Second, fermentation in the upper gut may result in a net loss or gain of AA to the animal. In addition, dietary effects on the efficiency of using bioavailable AA intake for tissue growth or milk production should be considered and may be attributed to endogenous AA losses in the hindgut and the metabolic costs associated with endogenous gut protein synthesis and losses. Ileal digestibility values may be expressed as apparent ileal digestibility (AID), standardized ileal digestibility (SID), or true ileal digestibility (TID). These terms are used to specify how ileal endogenous AA losses are reflected in digestibility values. Ileal endogenous AA losses may be separated into basal losses, which are not influenced by feed ingredient composition, and specific losses, which are induced by feed ingredient characteristics such as levels and types of fiber and antinutritional factors. Values for AID are established when total ileal outflow of AA (i.e., the sum of endogenous losses and nondigested dietary AA) is related to dietary AA intake. A concern with the use of AID values is that these are not additive in mixtures of feed ingredients. This concern may be overcome by correcting AID values for defined basal endogenous losses of AA, which yields SID values. Furthermore, if the AID values are corrected for basal and specific endogenous losses, then values for TID are calculated. However, reliable procedures to routinely measure specific endogenous losses are not yet available. It is recommended that basal ileal endogenous losses of AA should be measured in digestibility experiments using a defined protein-free diet and that these losses are reported with observed AID and SID values. It is suggested that SID values should be used for feed formulation, at least until more information on TID values becomes available.     

Two Methods of Vitrification Followed by In Vitro Culture of the Ovine Ovary: Evaluation of the Follicular Development and Ovarian Extracellular Matrix

The aim of this study was to evaluate the influence of two vitrification techniques on the extra cellular matrix (ECM) and ovarian follicular development. The ovarian cortex was fragmented (9 mm³) and divided into six groups, viz. fresh control, cultured control, vitrified by the Ovarian Tissue Cryosystem (OTC) method, conventional solid surface vitrification (SSV) method, OTC/cultured and SSV/cultured. Follicles from all the fragments were analysed for morphology, development and viability. The ECM was evaluated based on the condition of collagen and reticular fibres and the immunolocalization of type I collagen and fibronectin. After 7 days of culture, the tissue vitrified by OTC revealed a higher percentage (p < 0.05) of morphologically normal (30.66%) and viable (60.00%) follicles when compared with those vitrified using the SSV technique (21.33% and 23.00%). In all the fragments cultured, regardless of the vitrification method, a significantly higher percentage of developing follicles was observed when compared with the non‐cultured tissue. Analysis of the type I collagen showed increased immunostaining after the in vitro culture in the vitrified fragments. In conclusion, the OTC is better for preserving the follicular viability and morphology and maintaining the integrity of the extracellular matrix components of the ovine ovary.     

Pyrrolizidine alkaloidosis of cattle associated with Senecio lautu

Summary Serious incidents of pyrrolizidine alkaloidosis of cattle in 10 herds exposed to the Australian native plant, Senecio lautus (Asteraceae), were seen in central Queensland during 1988–1992. The deaths of 226 cattle were recorded. A mean of 8% of cattle died in affected groups (range 2 to 58%). Sickness and deaths usually occurred some months after access to S lautus. Typically, affected cattle lost body condition to the point of emaciation before dying and had persistent diarrhoea. Some animals developed abnormal behaviour and died after a shorter illness. Liver specimens from affected cattle in all herds contained lesions consistent with pyrrolizidine alkaloidosis. Thin layer chromatography of extracts of blood and liver samples from cattle from 5 herds detected pyrrolic metabolites. The identity of these was confirmed by mass spectroscopy on samples from one herd. Unseasonal autumn and winter rain after a dry summer appeared to favour growth of S lautus at the expense of other pasture species. A subsequent dry period promoted consumption of S lautus and was followed by a cluster of poisoning incidents.     

The intravenous administration of johnin in the diagnosis of paratuberculosis in practice

The diagnostic value of the intravenous injection of 1.6 or 3.2 ml of johnin was evaluated in a total of 116 cattle. The sensitivity was 84% with clinically suspect cattle. A general reaction occurred frequently as well as elevation of body temperature (average 1.47 degrees C). The observance of a general reaction was a good additional source of information when evaluating the test. There was no significant difference in elevation of temperature between the cattle injected with 1.6 ml and those injected with 3.2 ml. A combination of diagnostic techniques such as the complement fixation test, intravenous johnin test, microscopic examination of the faeces and a biopsy examination of the rectal mucosa were necessary, in order to confirm the diagnosis of Johne's disease. In this manner a diagnosis can be confirmed with clinically suspect cattle in 96% of the cases. The sensitivity of the intravenous johnin test was considerably lower in cases of non-clinical Johne's disease.