J.J. Ramos

Variations of clinical biochemical parameters of laying hens and broiler chickens fed aflatoxin-containing feed.

Two groups of 32 laying hens (Hyssex Brown) and two groups of 32 23-day-old (Hybro) broiler chickens were fed 2.5 and 5 parts/10(6) of aflatoxin in their diet for 4, 8, 16 and 32 days; 16 hens and 32 chicks were maintained as control groups (0 parts/10(6)). After the intoxication period, a clearance period was established of 1, 2, 4 and 8 days. Relative weights of liver and kidneys significantly increased in intoxicated hens, but not in broiler chickens. Histological lesions in both types of bird consisted of hepatic cell vacuolation with fatty infiltration. There was a significant decrease (P< 0.001) in egg production in the 5 parts/10(6) group, which started to recover during the clearance period. No morbidity or mortality due to the aflatoxicosis were observed in either type of bird. In intoxicated laying hens, cholesterol levels were not significantly (P> 0.05) different from control values, but triglyceride levels decreased (P< 0.001) in both intoxicated groups. The effect of aflatoxin on calcium and phosphorus levels was important, because on the 4th day their values decreased significantly. Aspartate aminotransferase (AST) serum levels remained normal, whereas alanino aminotransferase (ALT) activity decreased in both intoxicated groups. The activity of serum lactic dehydrogenase (LDH) and gammaglutamil transferase (GGT) increased significantly. In intoxicated broiler chickens, aflatoxins did not alter (P> 0.05) the biochemical parameters studied, except that the serum calcium concentration was lower in the 5 parts/10(6) group. These data indicated that in intoxicated laying hens, a severe clinical biochemical alteration was produced, and that this together with the hepatic lesions observed in hens and broilers may aid disease diagnosis.

Aflatoxins and their Metabolites in the Tissues, Faeces and Urine from Lambs Feeding on an Aflatoxin‐Contaminated Diet

Twenty-four lambs were intoxicated with 2.5 mg of aflatoxin (AF) kg -1 in their feed for 21 days. Twelve lambs were slaughtered at day 21 and the remaining animals had an 8 day clearance period. Aflatoxins and their metabolites were detected in liver, kidneys, faeces and urine using TLC and fluorescence densitometry. During the intoxication period, the samples gave a wide range of concentrations, the lower extreme being in the liver and the kidney (0.03 μg kg -1 of AFG 1 ) and the higher extreme in faeces (61.82 μg kg -1 of AFM 1 ) and urine (27.84 μg litre -1 of AFM 1 ). The average value of AFB, (1.94 ± 0.9 μg kg -1 ) was higher than AFM 1 (0.35 ± 0.17 μg kg -1 ) in the liver. In the kidney AFM 1 (5.45 ± 4.01 μg kg -1 ) was higher than AFB 1 (1.29 ± 0.84 μg kg -1 ). There were higher concentrations of AFM 1 (27.2 ± 16.1 μg kg -1 , 7.37 ± 6.53 μg litre -1 , respectively, of average level) in faeces and urine, than of AFB 1 (17.25 ± 8.1 and 1.78 ± 1.57 μg litre -1 , respectively). AFB 2a appeared in the kidney (0.05 ± 0.03 μg kg -1 ) and urine (0.35 ± 0.25 μg litre -1 ). The clearance time of AFB 1 from the faeces was less than or equal to 8 days and in all samples aflatoxin residues were still detected on the 8th day of the clearance period although in low quantities. These results suggest that aflatoxin transfer to and elimination by the liver and the renal tissue is small and that the danger to humans consuming lamb meat is also small. The examination of the faeces and urine could be useful as markers to detect lambs consuming a contaminated diet.

CHANGES IN THE PROTHROMBIN TIME, HAEMATOLOGY AND SERUM PROTEINS DURING EXPERIMENTAL AFLATOXICOSIS IN HENS AND BROILER CHICKENS

Two groups of 32 laying hens and two groups of 32, 23-day-old broiler chickens were given 2.5 and 5 mg kg-1 of aflatoxin in their diet for four, eight, 16 and 32 days; 16 hens and 32 broiler chicks served as control groups. In the laying hens, aflatoxicosis was characterised mainly by an increase in prothrombin time, and decreases in total plasma proteins and albumin levels; there were increases in red blood cell (RBC) counts and haematocrit which were greater in the group fed 5 mg kg-1. There was a decrease in beta-globulins and an increase in gamma-globulins. In the broiler chickens, there was only a slight increase in prothrombin time and a decrease in RBC counts. This data proves the good sensitivity and utility of prothrombin time values as an indicator of aflatoxicosis in birds.

Clinical chemical values and variations in Rasa Aragonesa ewes and lambs

Reference values of biochemical parameters in serum of Rasa Aragonesa ewes and their physiological variations were determined. Total proteins were 53.0–80.0 g/l, glucose 2.17–5.13 mmol/l, cholesterol 0.83–2.31 mmol/l, total bilirubin 1.85–6.49 μmol/l, urea 3.15–10.39 mmol/l, GGT 36–93 U/l (37°C), ALAT 11–33 U/l (37°C) and ASAT 71–209 U/l (37°C). Ewes were divided into three groups: A, 1- and 2-year-old ewes; B, ewes 3 and 4 years old; C, older ewes. Age had significant influence (P<0.05) on ASAT only during pregnancy, with higher levels for younger ewes. Blood parameters in lambs were determined at 5–10 d of life (nursing), 25 to 30 d of life receiving their mothers milk and 80–90 g of feed; and 45 to 50 d of life, weaned, receiving only solid feed. Serum urea and ALAT tended to increase with age, whereas total protein, globulins, cholesterol and GGT decreased with age. These values are of practical importance in the diagnosis of diseases and metabolic disorders in Rasa Aragonesa ewes and lambs under field conditions.

EFFICACY OF PHOSPHOMYCIN IN THE CONTROL OF ESCHERICHIA COLI INFECTION OF BROILER CHICKENS

Seventy-five 25-day-old broilers were divided into three groups: group I unmedicated and challenged with E. coli O78:K80; group F infected and treated with 150 ppm of phosphomycin in their drinking water, and group C acted as a control. Their weights, feed intake, clinical signs, macroscopic lesions, E. coli reisolation, and serum biochemistry were compared. Group F showed fewer symptoms and gross lesions than those from group I while the average daily gain, bodyweight, and feed intake were similar to the control group. E. coli was reisolated in 32 per cent of the livers and spleens from group I, compared with 4 per cent of liver and 8 per cent of spleens from group F. There was an increase in the levels of total protein and globulins in group I but not in group F. These results provide evidence of the therapeutic efficacy of phosphomycin in the control of an experimental E. coli infection in broiler chickens.

Biochemical Changes in Apparently Normal Sheep from Flocks Affected by Polioencephalomalacia

Blood samples were obtained for determination of the activities of lactate, pyruvate and erythrocyte transketolase, and faeces as samples for estimation of thiaminase, from 190 apparently healthy sheep from 19 flocks in which at least one animal had been diagnosed with polioencephalomalacia (PEM), from 59 control animals and from 7 affected by PEM. Feed and pasture grass samples were collected for thiaminase analysis and thiaminase was assayed in ryegrass and fescue. Decreased erythrocyte transketolase activity, accompanied by a corresponding rise in the thiamin pyrophosphate effect, and estimation of the thiaminase content in faeces, may be useful diagnostic procedures by which to identify periods of greater risk, during which animals could develop PEM. The changes in the diet probably acted as a primary factor for microbial production of thiaminases in replacement ewes. In these, the prevalence was higher in the spring months.

Alterations in the performance, haematology and clinical biochemistry of growing lambs fed with aflatoxin in the diet

Twenty‐three male lambs were fed 2.5 ppm of aflatoxin for 21 days. Thirteen lambs constituted the control group. Twelve lambs given toxin and six from the control group were killed at 21 days. The remaining animals were killed 8 days later. To determine haematological and biochemical parameters, samples of blood were obtained at 0, 7, 14 and 21 days of exposure and at 1, 2, 4 and 8 days after exposure. The most sensitive indicator of intoxication was the reduction in body weight (17 ± 2.2 kg−1 body wt. in intoxicated lambs and 19.2 ± 1.8 kg−1 body wt. in the control group; P ⋙ 0.01) and in the average daily weight gain (133 ± 79 g day−1 in the intoxicated group and 254 ± 105 g day−1 in the control group; P ⋙ 0.001) from the 14th day onwards. Lambs fed with aflatoxins had relatively smaller liver weights and higher kidney and spleen weights than lambs from the control group. Feeding aflatoxins increased the erythrocyte count and the mean corpuscular haemoglobin concentration and decreased the mean corpuscular volume and mean corpuscular haemoglobin values. An elevation in the levels of globulins with an increase of the beta and gamma fractions and no variation in total protein and albumin was observed in lambs fed on aflatoxins. Urea levels and the alkaline phosphatase and glutamate dehydrogenase enzymatic activities decreased as a consequence of intoxication, whereas gamma‐glutamyl transferase was increased. During the clearance period, haematological values regressed towards basal values, but biochemical parameters remained unchanged. These results suggest that lambs are sensitive to the toxic effects of the aflatoxins and that the determination of zootechnical parameters is a better aid to the diagnosis of intoxication than haematological or biochemical analyses.

Natural border disease virus infection in feedlot lambs

Border disease is caused by border disease virus (BDV, a pestivirus from the family Flaviviridae ) infection in sheep and goats (Vantsis and others 1976). BDV infection causes sizeable economic losses in sheep production around the world. In Spain, serological surveys have found 100 per cent flocks and 8–93 per cent sheep seropositive, respectively (Valdazo-Gonzalez and others 2006). BD is considered a congenital disease, but infections in healthy animals at all age groups may also occur. These are named acute infections and are characterised by transitory leucopaenia and fever associated with viraemia (Nettleton and others 1998). The aim of this study was to evaluate the impact of these acute infections in lambs in a commercial feedlot. A longitudinal observational study in a feedlot located in Aragon (Spain) was carried out. Lambs were supplied to the feedlot at minimum 10 kg bodyweight (BW) (45 days old), housed in groups of 250–300 per pen and slaughtered at 25–35 kg BW (about 45 days later). Thirty-six male lambs were randomly selected, ear-tagged, weighed, clinically evaluated and sampled on days: 0 (day lambs entered the feedlot), 14, 27 and 41. From each lamb, whole blood in anticoagulant solution and serum samples for haematological, virological and serological studies were taken. Haematological analysis with an electronic counter …

Chronic Proliferative Rhinitis associated with Salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) in Sheep in Spain

A chronic proliferative rhinitis in sheep associated with Salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) is described. Ten adult sheep from eight traditionally managed Rasa Aragonesa flocks located in Aragon (Spain) were studied. Clinical signs began with bilateral thick mucus nasal discharge, wheezing and snoring and progressed to partial or complete obstruction of the nostrils. Necropsy examination revealed swollen ventral nasal turbinates with a roughened mucosal surface partially covered by small polyps. Histopathology revealed chronic proliferative rhinitis with a predominant population of neutrophils that infiltrated the mucosal epithelium. Plasma cells and macrophages were present in the lamina propria. Organisms expressing Salmonella antigen immunohistochemically were detected within epithelial cells. Salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) was isolated as a sole microorganism from nasal swabs taken from five animals. The implication of finding this bacterium in various diseases in sheep and its role as a potential zoonosis are discussed.

Effect of aflatoxicosis on blood mineral constituents of growing lambs

The aim of this work was to study alterations of mineral constituents of blood in lambs intoxicated with aflatoxins and recuperation after 8 days of clearance time. Twenty-three male lambs (Rasa Aragonesa) were intoxicated with 2.5 ppm of aflatoxins for 21 days and 13 lambs were maintained as the control group (0 ppm of aflatoxins). Clearance time was 8 days. Samples of serum and plasma were obtained at 0, 7, 14, and 21 days of intoxication and at 1, 2, 4, and 8 days after aflatoxin withdrawal. Main mineral constituents were determined: Ca, P, Mg, Na, K, Cu, and Zn. A decrease (P ≤ 0.05) in plasma Zn was observed at the 14th day of intoxication. Ca, P, Mg, and K levels were lower by Day 21. Cu levels increased (P ≤ 0.05) compared with controls. Na levels remained in the control range of lambs (P ≥ 0.05). During the clearance time, Cu level returned to control values by Day 4, Ca and K by Day 8, whereas P, Mg and Zn remained lower (P ≤ 0.01). These results indicate that during aflatoxicosis in lambs a severe alteration in the mineral metabolism or absorption is produced, mainly due to hepatic and renal lesions and the decrease in feed intake observed in this study.