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ThesisItem Open Access Influence of different levels of energy on growth performance of crossbred pigs(Department of Animal Nutrition, College of Veterinary and Animal Sciences, Mannuthy, 2001) Rekha, P; KAU; George, MathenAn experiment was conducted to assess •the influence of different levels of energy on the growth performance of crossbred (Large White Yorkshire x Desi) pigs. Fifteen male (castrated) and fifteen female weaned crossbred piglets with an average body weight of 12.9 kg were divided into three equal groups as uniformly as possible with regard to age, sex and body weight. The three groups of piglets were maintained on three rations with 16 per cent crude protein but differing in their energy content, viz., 2800 kcal (T1), 3000 kcal CT2) and 3200 kcal (TI) of digestible energy (DE) per kg. The average daily gains recorded for the three groups T1, T2 and TI were 262.9, 302.0 and 362.8 g respectively. The cumulative feed conversion efficiencies were 6.0, 5.2 and 4.1 for the groups T1, T2 and TI respectively. The values recorded for TI were higher (P<0.01) than those for T1 and T2. The digestibility coefficients of nutrients except that of crude fibre and crude protein were found to improve with increase in the energy content of the rations. Study of the carcass traits revealed that the body weight at slaughter and dressed weight without head improved as the energy content of the rations increased. However, dressing percentage, carcass length and back fat thickness were not significantly influenced by the energy content of the ration. The cost of feed per kg weight gain of animals was significantly lower (P<0.01) for the dietary treatment T3 compared to that of T2 and Tl, the values being Rs.49.90, 43.30 and 34.10 for Tl, T2 and T3 respectively. The above results indicate that crossbred pigs require 3200 kcal of DE/kg of the ration for better growth performance provided the crude protein level is maintained at 16 per cent.ThesisItem Open Access Investigations on etio-pathology of vomiting in dogs(Department of Clinical Medicine, College of Veterinary and Animal Sciences, Mannuthy, 2001) Muraly, P; KAU; Baby, P GThe study "INVESTIGATIONS ON ETIO-PATHOLOGY OF VOMITING IN DOGS" was conducted in 20 dogs to evaluate ultrasonography and radiography as diagnostic tools in vomiting dogs; to assess hydration status, electrolyte and acid-base balance in vomiting dogs and to correlate clinico-pathologic findings with radiographic and ultrasonographic changes. Various parameters such as history, physical examination, hydration status, ultrasonography, radiography-plain and contrast, haematology, serum biochemistry, and wherever possible histopathology were studied. Most of the dogs under study had bile stained watery vomitus but dogs with pyloric stenosis had frothy or watery white vomitus. The frequency of vomiting in dogs with gastritis and gastrointestinal (GI) obstruction was two to seven times per day, it was variable in dogs with hepatic and renal disorders, but was associated with food intake in dogs with pyloric stenosis. Physical examination was found useful in dogs with GI obstruction, while it was non-specific in dogs with gastritis and renal disorders. Capillary refill time (CRT) and degree of sunken eye balls were helpful to assess dehydration. Estimation of volume of packed red cells (VPRC) was found beneficial to assess dehydration unless the dogs are anemic. Ultrasonography could not identify any lesions in dogs with gastritis, but was useful to detect GI obstructions due to pyloric stenosis, intussusception and foreign body and to characterise lesions in the parenchymal organs like liver and kidney. While plain radiographs could give indication to possible non-radiopaque GI obstructions, contrast radiography was required to confirm. Radiography could not identify any lesions in dogs with gastritis, hepatic and chronic intestitial nephritis. Hypokalemia with metabolic alkalosis was the significant electrolyte and acid-base derangement in dogs with vomiting due to gastritis and GI obstructions.ThesisItem Open Access Immunodiagnosis of bovine gastrothylacosis using coproantigens(Department of parasitology, College of Veterinary and Animal Sciences, Mannuthy, 2000) Kandasamy, A; KAU; Devada, KA study was conducted on the prevalence of paramphistomatidosis in Thrissur from June 1999 to May 2000, feasibility of coproantigen detection by ELlSA and comparison of sensitivity of ELlSA using coproantigens and ELlSA using serum antibodies in diagnosis of gastrothylacosis, caused by Gastrothy/ax crumenifer, in cattle. It was noted from the registers maintained at the University Veterinary Hospitals at Kokkalai and Mannuthy and that at the Department of Veterinary Parasitology, College of Veterinary and Animal Sciences, Mannuthy, that out of a total number of 1534 faecal samples from bovines examined, 253 (16.5 per cent) animals were found to be positive for amphistome eggs with the maximum prevalence (23 per cent) in June and July. Generally the infection was prevalent throughout the year. An indirect ELlSA using rabbit hyperimmune serum against somatic antigens of G. crumenifer was performed to detect coproantigens in faecal samples collected from 100 known G. crumenifer infected cattle. Seventy four samples were found to contain detectable levels of coproantigen indicating a sensitivity of 74 per cent. Serum samples collected from the same infected cattle were tested for antibodies to G. crumenifer by an indirect ELlSA using somatic antigens. Fifty one samples were found positive for antibodies indicating a sensitivity of 51 per cent. It was seen that when 43 cattle were positive for both coproantigens and serum antibodies, 18 cattle were negative for both of them. Although 31 cattle which were negative for serum antibodies were found positive for coproantigens, eight cattle negative for coproantigens were found positive for serum antibodies. The results showed that coproantigen detection, which revealed a higher sensitivity than the detection of serum antibodies by ELlSA, is feasible for the diagnosis of gastrothylacosis in bovines.ThesisItem Open Access Effect of processing and freezing procedures on the acrosome morphology of buck spermatozoa(Department of Animal Reproduction, College of Veterinary and Animal Sciences, Mannuthy, 1998) Ranjini, A; KAU; Prabhakaran Nair, KSix pooled semen samples (two ejaculates) of good quality from five Malabari crossbred bucks were processed and frozen in two different protocols to evaluate the effect of processing and freezing procedures on the acrosome morphology of buck spermatozoa. In protocol I, the samples were diluted 10 fold in Tris buffer before centrifuging twice and the final pellet was re-suspended in the non glycerolated fraction of Tris yolk diluent. The sample was glycerolated (six per cent), equilibrated (four hours), frozen (eight minutes), and thawed (250 C for 30 seconds). In protocol 11, centrifugation was done only once, after 15 fold dilution in Tris buffer. The re suspended pellet was glycerolated (seven per cent), equilibrated (three hours), frozen (10 minutes) and thawed (60° C for 10 seconds). The semen characters such as motility, live sperm, sperm abnormalities and acrosome abnormalities were evaluated at the end of washing and initial extension (stage I), cooling to 5° C (stage II), glycerolisation and equilibration (stage Ill) and freezing and thawing (stage IV). The results were compiled to evaluate the effect of different processing and freezing procedures on the semen characters in general and acrosome morphology in particular. The semen sample used for split sample dilution had a mean volume of 1.3282± 0.067 ml, creamy in colour, DDDD density, ++++ mass activity, pH of 7.275 2± 0.040 and a concentration of 2972 2± 293 millions per ml. No significant difference in the above semen characters were found between bucks. The initial sperm motility of 82.000 2± 0.606 was found to drop significantly during processing and freezing and the final post thaw motility obtained was 44.000 2± 0.790 in protocol I. Similarly in protocol II the initial motility dropped from 81.375 2± 1.089 to 44.750 2± 1.075 at the end of stage IV. Even though there was significant drop in motility between stages in both the protocols, there was no significant difference in the corresponding stages of the two protocols. It could be inferred that good post thaw motility was obtained in both the protocols. The fact that a single washing and centrifugation was only adopted in protocol II makes it a more acceptable procedure for buck semen freezing. The mean live sperm percentage of fresh semen was evaluated using both NE and NEG staining technique. The percentage of live sperms of 90.050 2± 0.801 was found to decrease to 54.250 2± 0.593 after freezing and thawing in protocol by NE staining. Similarly in protocol 11, the mean percentage of live sperms was found to reduce to 53.125 2± 0.793 with the same staining. Even though there was significant difference in the live sperm percentage between stages within protocol I and II no significant difference in the live sperm percentage between the corresponding stages of protocol I and I I . With NEG staining the initial live sperm percentage of 80.850 ± 1.494 was found to drop to 54.875 ± 0.677 in protocol I as against 53.400 ± 0.730 in protocol II. While there was significant difference in the live sperm percentage between stages within protocol I and II there was no variation between corresponding stages of the two protocols. A significantly lower percentage of live sperms was recorded with NEG staining when compared with NE staining probably on account of the fact that the differentiation of live and dead sperm was difficult in the former staining method as live sperms were stained light blue instead of colourless. The mean percentage of abnormal sperms of 3.050 ± 0.245 in fresh semen did not register any significant increase during processing. However, there was significant increase in the percentage of sperm abnormalities during freezing and thawing with the final abnormality percentage of 7.125± 0.706 in protocol I and 6.300± 0.36 in protocol II. The initial acrosomal abnormality of 8.825 in the fresh semen steadily rose to 23.375 in protocol I as against 19.825 in protocol II at the end of stage IV. There was no significant difference in the percentage of various acrosomal abnormalities between corresponding stages of the two protocols. However, there was significant increase in the acrosomal abnormalities during glycerolisation, equilibration, freezing and thawing under both the protocols. It was concluded that the processing and freezing under two different protocols did not significantly alter the post thaw motility, percentage abnormal and dead sperms and acrosomal abnormalities. A good post thaw motility and low acrosomal abnormality was obtained with a single washing of buck semen with 15 fold Tris buffer which was comparable with double washing with 10 fold Tris buffer.ThesisItem Open Access Effect of probiotic supplementation on the performance of broiler chicken(Department of Poultry Science, College of Veterinary and Animal Sciences, Mannuthy, 2001) Sabitha Mahaboob Kadari, A; KAU; Elizabeth, V KThe effects of different levels of pro biotic (Lactobacillus acidophilus, Streptococcus faecium and Yeasacc 1026) supplementation• at 0.025 and 0.05 per cent of the ration on the performance of broiler chicken were evaluated using 144, one-day old, commercial broiler chicks for a period of eight weeks. The birds were divided into three dietary treatment groups viz., standard broiler ration (T 1), standard broiler ration with 0.025 per cent probiotic (T 2) and standard broiler ration with 0.05 per cent probiotic (T3). Standard broiler ration was formulated as per Bureau of Indian Standards (1992) specification for broiler chicken feed. The 0.025 per cent probiotic supplemented birds showed a significantly higher (P<0.05) body weight upto six weeks of age. At the end of eight weeks of age, the 0.05 per cent probiotic fed birds grew faster. The body weight gain was significantly higher in 0.025 per cent probiotic supplemented group upto six weeks of age but was statistically non-significant upto eight weeks of age. The feed intake was not statistically significant throughout the experimental period. Eventhough the feed efficiency was significantly (P<0.01) better in the group fed with 0.025 per cent probiotic at the end of second week, it was statistically non-significant at sixth and eighth weeks of age. The protein efficiency was not significantly different throughout the experimental period. The serum cholesterol levels were significantly (P<0.01) reduced in both the probiotic supplemented groups. The serum protein level was not affected by probiotic supplementation. The processing Yields did not show any significant difference among treatments. The mortality percentage was not affected by treatments. Cost of production of broilers in the 0.025 per cent probiotic group was lower when compared with other two groups at the end of six weeks of age, while it was lower in the 0.05 per cent probiotic supplemented group at the end of eight weeks of age. It can be concluded that probiotic supplementation in standard broiler ration at a lower level was beneficial in the early stages of growth.ThesisItem Open Access Induction of parturition and evaluation of postpartum fertility in crossbred cows(Department of Animal Reproduction, Gynaecology and Obstetrics, College of Veterinary and Animal Sciences, Mannuthy, 2010) Sheeja, S; KAU; Aravinda Ghosh, K NA preliminary study was conducted by collecting data regarding gestation length and details of calving among crossbred cattle of the University Livestock Farm and local breeds belonging to “ICAR Scheme on Conservation of Germplasm of Vechur Cattle”. The mean gestation length of crossbred cattle of ULF was 274 ± 0.48 days and that of Vechur scheme was 282 ± 0.98 days. The average birth weight of new born calf at ULF was 26.52 ± 0.39 kg and that of Vechur was 10.43 ± 0.12 kg. The sex ratio of male and female was 1: 0.9 and 1: 1.2 for ULF and Vechur scheme respectively The main experiment was undertaken to develop a suitable protocol for induction of parturition in crossbred cattle with prolonged gestation and to assess the postpartum fertility of these animals. The study was performed in 24 pregnant animals of the University Livestock Farm and private farms near by Mannuthy during the period from December 2008 to February 2010. In all animals in group I, II and III, the drug was administered for inducing parturition on 286th day of gestation. In group 1, 24 mg of dexamethsone, in group II 500µg of prostaglandin analogue (cloprostenol) and in group III, a combination of 12 mg of dexamehasone and 250 µg cloprostenol was administered intramuscularly and group IV acted as control. The mean time taken in hours for induction of parturition in group I to III was 39.50 ± 1.26, 30.50 ± 2.17 and 26.90 ± 1.80 respectively and the least time was recorded in combination group. The duration for first stage of labour in groups I to IV was 4.00 ± 0.16, 3.12 ± 0.15, 3.24 ± 0.02, 4.49 ± 0.12 hours respectively and for second stage was 1.27 ± 0.02, 1.12 ± 0.14, 1.21 ± 0.12, 1.53 ± 0.10 hours respectively. The mean time for the expulsion of placenta was 6.67 ± 0.33, 6.35 ± 1.87, 3.02 ± 0.13 2.74 ± 0.14 hours respectively. The mean weight of the placenta for the groups was 2.87 ± 0.43, 3.50 ± 0.54, 3.00 ± 0.28, 3.60 ± 0.25 kg and the mean number of cotyledons were 89.50 ± 0.76, 91.20 ± 0.60, 90.5 ± 0.84, and 91.50 ± 0.76 respectively. The incidence of dystocia in groups I to IV was 50, 0, 33.33 and 50 per cent respectively. The incidence of retention of foetal membranes in groups I to IV was 50, 33.33, 16.66 and 16.66 per cent respectively. In group I, the incidence of postpartum prolapse of genital organs, downer cow and mastitis were recorded as 16.66 per cent each. The sex ratio for the groups I to IV was 1:1, 0.57: 1, 1:1 and 1:1. The mean birth weight in kg for the male calves was 29.33 ± 1.2, 26.65 ±6.5, 31.5 ± 3.40, 34.66 ± 2.03 respectively. Similarly the birth weight of female calves were 30.00 ± 1.15, 27.25 ± 1.97, 23.33 ± 2.40, 32.33 ± 1.20 kg respectively. There was steady increase in body weight of calves as age advanced in experimental and control groups, however there was no significant difference between groups in mean body weight gain. The mean peak yield in the present lactation for the experimental and control animals was 9.57 ± 0.58, 11.33 ±1.17, 11.67 ±1.54 and 13.17± 0.75 liters respectively. The corresponding values in the previous lactation for the experimental and control groups were 11.48 ± 0.48, 11.60 ± 0.75, 12.70 ± 0.47 and 13.50 ± 0.65 liters respectively. The day of peak yield in the present lactation was 25.00 ± 0.63, 21.66 ± 0.61, 22.33 ± 1.05 and 19.16 ± 0.79 days and the corresponding values in previous lactation were 19.80 ± 0.95, 18.70 ± 0.67, 20.30 ± 1.28 and 19.30 ± 0.63 days respectively. The disappearance of lochial discharge for the experimental and control groups was 20.16 ± 1.04, 17.31 ± 1.13, 17.17 ± 0.87, 21.00 ± 1.26 days respectively. The first postpartum oestrus was observed at 33.20 ± 1.25, 30.70 ± 0.88, 29.50 ± 0.76 days for experimental animals and for control animals it was 31.60 ± 0.76 days. Similarly, the second postpartum oestrus was on 59.00 ± 1.22, 51.83 ± 0.83, 48.33 ± 1.99, 53.83 ± 0.94 days respectively. Conception rate for the first AI in group I to IV was 0, 50, 50, and 33.33 respectively where as the overall conception rate for these animals was 16.66, 66.66, 83.33, 66.66 per cent respectively. The highest conception rate was obtained in group III. The mean calving to conception interval for the experimental and control animals was 91.50 ± 15, 77.66 ± 9.38, 74.00 ± 7.00 and 82.00 ± 13.97 days respectively Premature induction of parturition was carried out in four downer cows presented at Veterinary College Hospital, Mannuthy which failed with routine medical treatment and having the gestation length of 253, 285, 270 and 275 days. In the first two animals parturition was induced with prostaglandin and the time taken for induction was 48.30 and 31.20 hours respectively. In dexamethasone treated animal calving occurred at 51 hours after administration of drug. Similarly the time taken for induction in animal which treated with combination of dexamethasone and prostaglandin was 29.45 hours. All the three animals in which prostaglandin and its combination with dexamethasone, recovered from recumbent stage after delivery and had regained normal feeding habits. The animal treated with dexamethasone had not regained the normal condition and was advised disposal. But all the four calves survived in this experiment. The present study revealed that induction of parturition with prostaglandin alone in normal dose and its combination with dexamethasone at a lower dose were equally useful for successful induction of parturition in animals with prolonged gestation with least reproductive complications. When parturition was induced with dexamethasone milk yield was found to be reduced during early stages of lactation while when prostaglandin and its combination with dexamethasone were used reduction in milk yield was negligible. In animals in which parturition was induced with prostaglandin and its combination had normal disappearance of lochial discharge, early involution of uterus and had early normal postpartum oestrus and had fairly good overall conception rate. Further it is recommended that premature induction of parturition in downer cows when all other medical treatments have failed, prostaglandin or its combination with dexamethasone could ideally be used to induce premature induction of parturition to save the life of mother and new born.ThesisItem Open Access Isolation and identification of viruses from waterfowls seen in Kerala(Department of microbiology, College of veterinary and animal sciences, Mannuthy, 1997) Bindu, M S; KAU; Krishnan Nair, GIn the recent years, frequent outbreaks of poultry diseases have caused significant economic losses and among the various sources of infection, freeflying migratory birds and waterfowls are reported to be an important source for the introduction of disease to domestic flocks. These freeflying pirds and waterfowls abound in the waterlogged areas of Kerala especially Alleppey, Kottayam, Thrissur and Malappuram districts. Heavy losses were reported each year due to severe outbreaks of duck plague and duck pasturellosis resulting in the wiping out of the duck population in the state. This may be due to the introduction of the disease agents by migratory waterfowls. Hence a study was undertaken to elucidate the role of waterfowls in the spread of diseases to domestic poultry and ducks. A total of 52 waterfowls were caught from different parts of Kerala of which 15 were lesser whistling teals and 37 were gargany. Postmortem examination of these birds were carried out and the required materials were collected. Impression smears from the cut surface of the liver revealed intranuclear inclusion bodies in the hepatic cells in four cases (Bird Nos. 17, 23, 27 and 49) and two haemagglutinating agents were isolated from the cloacal swabs of the bird numbers 18 and 22. The haemagglutinating agents developed lesions in the chicken embryos which died 3 to 5 days after inoculation. the allantoamniotic fluid of the affected embryos agglutinated teal and chicken erythrocytes. The lesions exhibited by the embryos infected with Ta were congestion of the CAM and embryos while in T22 the embryos were stunted, curled and at the same time congested. The liver of the embryo had yellowish brown patches. The haemagglutination activity of both the viral isolates were tested with red cells of various species like cattle, horse, human '0', duck, rabbit and pig but was negative in all cases. Both the isolates lost their infectivity and haemagglutination property at 56°C for 30 min. the infectivity and HA activity of the viral isolates T18 and T22 were retained at pH 7.2 and were completely destroyed at pH 3.2 and pH 9. Both the isolates were sensitive to treatment with chloroform, revealing both as enveloped viruses, wherein the infectivity was completely lost and HA activity was considerably reduced. In the case of Tl8 HA activity was reduced from 512 to 16 and for T22 from 128 to 8. The nucleic acid types of the viral isolates were confirmed by inoculating the isolates to chicken embryo fibroblast cultures pretreated with 100 µg and 200 µg per ml of IudR which led to the conclusion that Ta was a RNA virus and T22 a DNA virus. The ELD50 of Ta and T22 were 107 ELD50/ml and 106 ELD50/ml. The ICPI, MDT and IVPI. were calculated as for NDV. The ICPI for the isolates were 0.83 and 0.30 for T18 and T22 respectively, MDT was 120 hr for both and the IVPI was calculated to be zero in both cases, indicating that both the isolates were nonpathogenic. In cell cultures both the isolates produced CPE which affected the whole monolayer by 96 hrs. In the case of Tl8 the CPE was characterised by rounding and clumping of cells, the infected cells showing a tendency to get separated from the neighbouring cells leaving long cytoplasmic strands, syncytium formation with four or five nuclei and severe cytoplasmic vacuolation. For T22 the CPE was characterised by rounding and cytoplasmic vacuolation and karryorhexis. Intranuclear and intracytoplasmic inclusion bodies could be demonstrated. The pathogenicity studies of both the isolates were carried out in one week old and six week old ducklings and chicken, for which both were nonpathogenic and did not exhibit any clinical signs or mortality. But viral infection was established in six week old chicks by virus isolation till the 14th day of infection from the cloacal swabs for both the isolates. The sera collected from these birds revealed an antibody titre of 16 for T¬18 and 8 for T22 indicating the infection. The antigenic relationship of the isolates was examined with NDV, EDS-76 and fish viruses (FV and F6), of which T22 did not show any antigenic similarity with any of the viruses. But T1B on the contrary exhibited antigenic relationship with the fishviruses FV and F6 but no antigenic similarity with NDV and EDS-76. The antigenic similarity exhibited by T18 with the fish viruses leads to the conclusion that waterfowls may be disseminating the viruses responsible for the outbreak of epizootic ulcerative syndrome in fishes. The morphological features of T18 by electronmicroscopy revealed an enveloped virus with a size of 150-185 nm with pleomorphic forms and peplomers of a length of 18-20 nm. Except the length of the peplomers it similated a paramyxovirus. The morphology of T22 was not studied due to technical defects.ThesisItem Open Access Haematological And Serum Biochemical Profile Of Intestinal Impaction In Elephants(Department of Clinical Medicine, College of Veterinary and Animal Sciences,Mannuthy, 1999) Jayakrishnan, T N; KAU; Alex, P CThe present study was undertaken to analyze the haematological and biochemical alterations in elephants affected with gastro-intestinal tract impaction. The epidemiology, clinical fmdings and haematology were the main items of observations. Six elephants affected with gastro-intestinal tract impaction lasting for more than four days in and around Thrissur district were utilized for the study. Six apparently healthy elephants in and around Thrissur district were selected at random and utilized as the healthy controls. The detailed history was collected using a questionnaire (Annexure I). Sample of whole blood and serum from the animals of the healthy and diseased groups were collected and analysed. Haematological values consisting ofESR, PCV, Hb, TEC, TLC and DLC were recorded. Urea nitrogen, glucose, sodium, chloride, potassium, total protein, creatinine, bicarbonate, lactate and AST in the serum were estimated using standard methods. Analysis of the data indicated that the disease was more common in male elephants than in females. The incidence was more in summer season i.e., during the season of festivals. Characteristic clinical symptoms were absence of defaecation ~, tttc!ife than 24 hours, varying degrees of straining, exudation from re~t»m ~rn1 Y~frfrg degrees of dehydration. Clinical data were within physiological limits on the day of collection of blood sample, i.e. on the fourth day after the development of clinical symptoms. A highly significant increase in PCV but without significant alterations in Hb, ESR, TEC, TLC and DLC were observed in elephants affected with gastro-intestinal tract impaction. Biochemical changes in blood included a highly significant increase in urea-nitrogen and lactate levels. Highly significant decrease in the level of chloride was noticed. Significant increase in the level of bicarbonate was noticed. Decrease in the levels of glucose and potassium in the affected elephants was significant. Variations in total protein, sodium, creatinine and aspartate amino transferase in the blood were not significant. Changes in the parameters observed in elephants with gastro-intestinal tract impaction in the present study indicated that mild metabolic alkalosis with hypochloremia and hypokalemia were associated with this condition. Intensive treatment with a balanced electrolyte solution! Dextrose saline/ gastric replacement solutions is recommended in the early stages of gastro-intestinal tract impaction.ThesisItem Open Access Determination Of Permissible Level Of Aflatoxin In Broiler Chicken Feed(Department of Pathology, College of Veterinary and Animal Sciences,Mannuthy, 1999) Arulmozhi A; KAU; Koshy VargheseThe study was undertaken to assess the effect of various levels of aflatoxin on the performance of broilers and to establish the permissible level of aflatoxin in the broiler feed. One hundred and eighty day old broiler chicks were divided into six groups of 30 birds each and were given feed containing graded levels of aflatoxin at 0, 20, 40, 60, 80 and 100 ppb for a period of 45 days. Feed intake, weekly body weight gain, feed efficiency, haemogram, serum profile, organ weight, residual aflatoxin in tissues and pathological changes in liver, kidney, bursa and spleen were studied at fortnightly intervals to evaluate its dose related effects. A dose dependent decrease in the daily feed intake and mean body weights were noticed in all the groups. The cumulative FeR was extremely poor at 80 and 100 ppb levels at sixth week of age. The toxicopathological changes in the birds varied in its intensity in relation with the level of aflatoxin in the feed, with most severe changes being at higher dose levels. The values of haemoglobin, PCV, total leucocyte count, Iymphocytes, total serum protein and albumin showed a decrease whereas the ESR, heterophil and serum enzyme were increased. The aflatoxin, even at 20 ppb levels caused degenerative and necrotic changes in liver and kidneys and the intensity of the lesions increased with higher levels of toxin. Attempt for regeneration and repair processes were well pronounced by the 30th and 45th day. Lymphoid depletion was a characteristic feature in bursa and spleen. Degeneration and lysis of lymphocytes with cys; formation was also seen in bursal follicles. Residual aflatoxin was detected in the liver and muscle in all groups by the 45th day. The net returns from the toxin treated birds showed a dose related decline compared to control and the loss in profit at 20 ppb level was marginal About 24 per cent of the poultry feed samples tested during the period from January to July 1999 were contaminated with aflatoxin quantitatively ranging from 20 to 200 ppb. The results of the present study shows that even at 20 ppb aflatoxin causes cellular and subcellular damage to the tissues. However, the economic loss at this level was marginal when compared to higher dose levels. Hence 20 ppb can be considered as permissible level in broiler chicken feed.
