Phenotypic drift in osmotic fragility of Sahel goat erythrocytes associated with variability of median fragility

A typical mammalian erythrocyte fragility phenotype (EFP) exhibits a sigmoidal curve of the dependence of fragilities (% haemolysis) on hypotonic saline concentrations, but the goat EFP tends to be hyperbolic. Physiological variation in median erythrocyte fragility (MEF) and the associated EFP of Sahel goats was  investigated. Erythrocyte osmotic fragility (EOF) was determined in hypotonic saline using heparinized venous blood from 47 goats (23 males and 24 non-pregnant dry females) aged 1-4 years and weighing 18.87 ± 6.32  (9-30) kg. Packed cell volume (PCV), erythrocyte count and mean corpuscular volume (MCV) were also  estimated. Low, medium and high EFP were based on MEF of < 7, 7-8 and > 8 g/L, respectively. MEF of all the goats was 7.5 ± 0.6 (5.9-8.4) g/L. Phenotypic drift from sigmoidal to hyperbolic EOF curve was observed at  the lower and upper limits of the phenotypic variation. Frequencies of occurrence of low, medium and high EFP were not different (p > 0.05) between males and females. Fragiligrams of low, medium and high EFP separated at erythrocyte fragilities of 10-70% and saline tonicity of 7-8 g/L. The saline concentrations causing fragilities of 10-70% differed (p < 0.05) among the phenotypes. There was no correlation (r = -0.28, -0.30; p > 0.05)  between MEF and MCV or PCV, and between PCV and MCV. In conclusion, phenotypic drift in EOF occurred in  Sahel goats without influence by erythrocyte parameters and represented the physiological variability of EOF  endpoint estimates that would serve as reference limits in evaluation of erythrocyte membrane defects. Keywords: Erythrocyte size, Median fragility, Osmotic fragility, Phenotypic drift, Sahel goa

Quantified Effects of Late Pregnancy and Lactation on the Osmotic Stability of Sahel Goat Erythrocytes

Pregnancy and lactation are physiological states mediated by metabolic and endocrine factors capable of affecting erythrocyte osmotic stability. Alteration in erythrocyte osmotic fragility (EOF) during late pregnancy and lactation was investigated in 46 apparently healthy adult Sahel goats weighing 18- 30 kg consisting of 16 non-pregnant dry (NPD), 15 pregnant (PRE) and 15 lactating (LAC) animals. The PRE and LAC were in third trimester and nursing periods, respectively. Packed cell volume, erythrocyte count, mean coruscular volume and EOF were determined with heparinised venous blood using standard methods . Erythrocyte parameters of NPD, PRE and LAC did not vary significantly (p >0.05). The mean fragilities of NPD, PRE and LAC varied significantly (p < 0.05) at saline concentration of 8 g/L, with left and right shifts of PRE and LAC fragility curves from NPD curve at saline concentrations of 7-8 g/L, respectively. At 10-70% haemolysis, mean saline concentrations increased (p < 0.05) by 0.31 ± 0.07 (0.2-0.4) g/L for LAC and decreased (p < 0.05) by 0.19 ± 0.09 (0.1-0.3) for PRE from mean values for NPD, so that the  aggregate shift of mean saline concentrations between PRE and LAC was 0.50 ± 0.10 (0.40-0.70) g/L. EOF decreased in late pregnancy and increased during lactation, perhaps, due to changes in the composition of erythrocyte membranes associated with the physiologic states.Keywords: Erythrocyteosmotic stability, osmotic fragility, late pregnancy, lactation, Sahel goa

Prevalence of Newcastle disease virus antibodies in sera and eggs of helmeted guinea fowls (Numida meleagris galeata pallas) in Borno and Yobe States, Nigeria

The seroprevalence and maternal antibody profiles to Newcastle disease virus infection of guinea fowls  were studied using haemagglutination inhibition (HI) test, in Borno and Yobe States of Nigeria. Of 822 sera  and 354 egg yolk extracts tested, 327 (39.8%) and 242 (68.4%) were positive for NDV antibodies  respectively. The seroprevalence was significantly higher (P< 0.05) in the dry (47%) than in the rainy  (32.8%) seasons. Maternal antibodies in egg yolk extract (sampled during the rainy season), were  significantly (P< 0.05) higher (68.4%) than the seroprevalence. The frequency distribution of antibody  titers were skewed with 79.8% and 63.2 % of sera and egg yolk respectively having reciprocal antibody  titres ≤ 20. The geometric mean antibody titre was higher (P< 0.05) in the dry season (3.7±2.0) than in  the rainy season (2.5 ±1.7). The geometric mean titre was also higher (P<0.05) in egg (8.9±2.5) than in  sera (3.1±1.9). These results showed that Newcastle disease virus is enzootic among guinea fowls in Borno and Yobe states, especially in the dry season. The geometric mean titer of antibodies from egg yolk (8.9)  was below the protective reciprocal titres ≥35.4, suggesting the need for control measures immediately  after hatching. In addition, birds with titers ≤ 35.4 are partially immune and may shed the virus without a clinical disease when infected thereby becoming a risk to in-contact birds.Keywords: Egg, Guinea fowls, Maternal antibodies Newcastle disease, Seroprevalenc

The role of intraperitoneally administered vitamin C during Trypanosoma congolense infection of rabbits

The effects of daily intraperitoneally administered doses of 100 mg/kg bd. wt. vitamin C on levels of some endogenous antioxidants as well as hepatic and renal function were investigated in a group of rabbits infected with a strain of Trypanosoma congolense (strain number: BS2/TC /SP28/P4). Values of parameters estimated in this group during and after 5 weeks of infection were compared with those from a group of similarly infected, but vitamin-free rabbits as well as two groups of healthy rabbits, one group of which was similarly treated with vitamin C. T. congolense infection caused significant (P<0.01) decrease in packed cell volume (PCV), blood and organ glutathione, plasma and liver ascorbic acid as well as serum creatinine. Treatment of infected animals with vitamin C kept the parasitaemia significantly (P<0.01) lower than in the vitamin-free infected animals after the 3rd week of infection. The vitamin treatment also prevented, to a significant (P< 0.01) degree (and in some cases completely), the disease-induced decreases in blood and organ glutathione (GSH) as well as plasma ascorbic acid. The trypanosomal anaemia was partially, but significantly (P<0.01) ameliorated by vitamin treatment. Infection without vitamin therapy also caused significant (P<0.01) increase in the levels of serum total bilirubin and proteins as well as aspartate and alanine aminotransferases. Vitamin C completely, or to a significant (P<0.01) degree, prevented the disease-induced increases in all these parameters. It was concluded that vitamin C at the dose and route used prevented the disease-induced depletion of endogenous antioxidants, hepatic dysfunction and to a significant degree, anemia.Key words: Trypanosoma congolense, antioxidant, oxidative damage

Sickness behaviour pushed too far – the basis of the syndrome seen in severe protozoal, bacterial and viral diseases and post-trauma

Certain distinctive components of the severe systemic inflammatory syndrome are now well-recognized to be common to malaria, sepsis, viral infections, and post-trauma illness. While their connection with cytokines has been appreciated for some time, the constellation of changes that comprise the syndrome has simply been accepted as an empirical observation, with no theory to explain why they should coexist. New data on the effects of the main pro-inflammatory cytokines on the genetic control of sickness behaviour can be extended to provide a rationale for why this syndrome contains many of its accustomed components, such as reversible encephalopathy, gene silencing, dyserythropoiesis, seizures, coagulopathy, hypoalbuminaemia and hypertriglyceridaemia. It is thus proposed that the pattern of pathology that comprises much of the systemic inflammatory syndrome occurs when one of the usually advantageous roles of pro-inflammatory cytokines – generating sickness behaviour by moderately repressing genes (Dbp, Tef, Hlf, Per1, Per2 and Per3, and the nuclear receptor Rev-erbα) that control circadian rhythm – becomes excessive. Although reversible encephalopathy and gene silencing are severe events with potentially fatal consequences, they can be viewed as having survival advantages through lowering energy demand. In contrast, dyserythropoiesis, seizures, coagulopathy, hypoalbuminaemia and hypertriglyceridaemia may best be viewed as unfortunate consequences of extreme repression of these same genetic controls when the pro-inflammatory cytokines that cause sickness behaviour are produced excessively. As well as casting a new light on the previously unrationalized coexistence of these aspects of systemic inflammatory diseases, this concept is consistent with the case for a primary role for inflammatory cytokines in their pathogenesis across this range of diseases

Testicular and related size evaluations in Nigerian Sahel goats with optimal cauda epididymal sperm reserve

Testicular sizes of animals are important for identification of those with adequate sperm production. The aim of this study was to define the testicular and related size estimates that would be associated with optimal cauda epididymal sperm counts (ESC) in Sahel goats based on postmortem evaluations. A stratified quota sample population of 125 male goats inclusive of all testicular sizes was taken at a slaughterhouse in Maiduguri, Nigeria. The bucks were aged 18-30 months and weighed 17.04 ± 2.99 (12-25) kg. Body, testicular and epididymal weights of each goat with other related size measurements were estimated. ESC was determined from homogenized tissue using a manual cytometer. At the cut-off ESC of >1.1 × 109 sperm heads, 66 (52.5%) of the goats had optimal ESC which was associated with testicular weight of 59.90 ± 16.10 (31.4-86.2) kg, gonado somatic index of 3.51 ± 0.69 (2.0-4.5) g/kg and scrotal circumference of 19.07 ± 1.29 (17.0-21.8) cm. The ESC correlated better with age than body weight of the animals and correlated also with testicular and scrotal size variables and epididymal weights. The size variables of the scrotum and testis correlated with one another. These findings provide data that may be used to anticipate adequate antemortem sperm reserve based on testicular size during preliminary selection of sires for breeding from a sexually mature Sahel buck population.Keywords: Optimal sperm output, testicular size, scrotal size, Sahel goat, Nigeri

The stability of the packed cell volume of anticoagulated bovine blood at refrigeration temperature

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