Abstract: Yolk retention and yolk sac infection is considered as an important cause of death in chicken as well as in guinea fowl, duck, turkey, quail and goose. The factors which slow down the rate of yolk absorption and may in turn lead to yolk retention are discussed. Yolk sac infection of bacterial origin is most important among these factors. Other factors which may contribute include type of initial feed, brooding temperature, prolonged exposure to hatcher environment and size of birds.
Abstract: A total of 100, day-old broiler chicks were randomly divided into 5 equal groups and kept under elevated temperature (93-97°F) to see the effect of ascorbic acid and acetylsalicylic acid on the feed conversion ratio (FCR), immune status and ratio of weight of bursa, thymus and spleen to body weight. Heat stress increased the FCR but decreased the immune response and ratio of bursa, thymus and spleen to body weight of the birds. Ascorbic acid and acetylsalicylic acid supplementation during heat stress had beneficial effects on FCR, immune status and ratio of bursa, thymus and spleen to body weight. Grossly, bursa, thymus and spleen of heat stressed birds were atrophied but in ascorbic acid and acetylsalicylic acid supplemented birds these organs were not atrophied. No specific histopathological changes were observed in all groups.
Abstract: In this study, 100 day-old broiler chicks were divided into two groups, A and B containing 50 birds each. Experimental infection with E. coli was given intra yolk to group A on day-l of experiment, while group B was kept as control. Parameters studied were examination of yolk sac, yolk sac:body weight ratio, antibody titer against Newcastle disease virus (NDV) and analysis of fractional serum proteins. Results showed that yolk sac infection with E. coli led to gross pathological changes of yolk sac (enlarged, discoloured, changed consistency and congested blood vessels). Yolk sac:body weight ratio was increased and geometric mean titer against NDV was decreased in serum and yolk of treatment group. Analysis of fractional serum proteins revealed that percentage area covered by most of serum protein fractions was decreased in treatment group as compared to control group. It was concluded that intra yolk infection with E. coli resulted in pathological changes of yolk sac, increased yolk sac:body weight ratio, decreased immunity and altered serum proteins profile of chicks.
Abstract: One hundred and sixty one-day-old layer chicks were divided into four experimental groups A, B, C and D, with 40 birds in each group. Group A was kept as control (non-vaccinated), group B was given vaccine but not medicated, group C was administered vaccine as well as multivitamins for 3 days post-vaccination, while group D was also medicated with aspirin for 3 days post-vaccination. The parameters studied were: heterophil/lymphocyte ratio, serum biochemical analysis (serum protein, glucose and cholesterol), antibody response against infectious bursal disease virus (IBDV). At the end of experiment (42nd day) adrenal glands from 10 randomly selected birds from each group were subjected to gross and histopathological examination and adrenal/body weight ratio was also determined. The results showed non significant difference among different groups. However, the group that was given multivitamins showed maximum immune response against IBDV while the aspirin therapy did not show any significant difference. It can be concluded that vaccine produced undetectable stress in layer chicks and the vitamin supplementation evidently showed as an immuno-potentiating effect.
Abstract: The present project was carried out to study the effect of experimental yolk sac infection with Staphylococcus aureus on immune status of broiler chicks. For this purpose, one hundred day-old chicks were divided into two groups A and B, having fifty chicks each. Confirmed pathogenic isolate of Staphylococcus aureus was inoculated into the yolk of each chick of group A, while group B acted as control group. Parameters studied included pathological examination of yolk sac, yolk sac weight/body weight ratio, antibody titres against Newcastle disease virus (NDV) in serum and yolk and analysis of fractional serum proteins. Results showed that yolk sac weight/body weight ratio was higher with marked pathological changes (abnormal colour, consistency and odour) were also observed in unabsorbed yolks of the infected group. Geometric mean titres of maternal antibodies against NDV were significantly lower in serum but higher in unabsorbed yolks of infected group than in control one. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used for serum protein analysis and percent area covered by each protein fraction was calculated. The percent area covered by most serum protein fractions was lower in infected chicks than the control chicks. It was therefore concluded that yolk sac infection (omphalitis) with S. aureus led to decline in the immunity.
Abstract: The present project was designed to detect the stress following vaccination (Eimeria vaccine) against coccidiosis in broilers and its management by using multivitamins and aspirin. The parameters studied were heterophil/lymphocyte ratio, total serum protein, serum glucose and serum cholesterol estimation, for three consecutive post vaccination days. At the end of experiment, on 42nd day, adrenal gland/body weight ratio and histopathology of adrenal gland was performed to assess any change. The results showed no statistically significant difference among difference groups. However, the group that was given multivitamins showed maximum weight gain and minimum stress, while the aspirin therapy did not show any significant difference.
Abstract: The present project was designed to identify the factors responsible for yolk retention in broiler chicks. Four different experiments were conducted to find out the effect of four factors (experimental yolk sac infection with Escherichia coli. off-feed period between hatching and housing, first feeding time in the poultry house and type of initial feed) on yolk absorption. Results of these experiments showed that yolk sac infection with E. coli led to decrease in rate of yolk absorption. Moisture and protein percentage was increased in infected yolk but fat percentage was not affected by yolk sac infection. On the other hand, post hatch starvation due to delay in housing and delay in first feeding did not affect rate of yolk absorption. Moisture percentage was not affected while fat absorption increased and protein absorption decreased due to fasting. It was also observed that feeding ground corn in early life of chick led to slow absorption of yolk contents as compared to feeding commercial starter ration and 2% sugar solution. Yolk composition was not affected by feeding commercial starter ration, ground corn and 2% sugar solution in early life of chick. It was concluded that experimental infection of E. coli and ground corn as initial feed affect the rate of yolk absorption in young broiler chicks.
Abstract: A study was conducted to observe the effect of intrayolk injection of gentamicin on experimentally induced omphalitis in broiler chicks. Escherichia coli was injected into yolk sac to induce omphalitis and treatment was done by intrayolk injection of gentamicin. Results showed that mortality decreased and feed intake increased after treatment. Intrayolk injection of antibiotic is suggested as an alternative to the oral administration for the treatment of omphalitis in chicks.
Abstract: The project was designed to observe the effect of type of initial feeding on yolk sac in broilers experimentally infected with Escherichia coli. For this purpose chicks were divided into 7 groups having 20 chicks each. On day 1, yolk sac infection was introduced in groups A, B, C, D, E and F while group G remained as control. Group A was fed wheat bran, group B fed on ground maize, group C fed on commercial starter ration (CSR) and 2% glucose solution, group D fed on CSR and 6% canola oil, group E fed on CSR and enzyme mixture, group F fed on CSR and group G fed on CSR for first five days of experiment. Simple CSR was fed to all groups after 5th day of experiment. Body weight, yolk sac weight, yolk sac/body weight index, estimated yolk sac absorption and chemical composition of yolk was studied for each group. Results of experiment showed that simple CSR give better results as initial feed in broilers infected with E. coli infection rather than using wheat bran, ground maize, 2% glucose solution with CSR, 6% canola oil with CSR or enzymes with CSR. It was observed that feeding commercial starter ration in E. coli infection, in early life of chick led to increase weight gain, decrease in yolk sac weight and yolk sac/body weight index, increased estimated yolk absorption and better absorption of moisture and protein from yolk.
