Effects Of Different Diets On Development Of Proventriculus And Their Relationship With Proventriculitis Of White Feather Broilers

Proventriculitis in broiler chickens is a kind of disease which is characterized by,poor growth and uniformity, low feed conversion ratio, as well as swollenproventriculus and desquamation in mucosal of proventriculus tract. Lots of reportshave been reported in this field, but there is no consistency. Some experts consideredthat it was caused by virus, others believed that it might be caused by other factors.This study was conducted to evaluate the effect of non-pathogenic factors, i.enutrition level, feed form and feed particle sizes on development of proventriculusand the relationship with proventriculitis, to disscuss the influence of feed nutritionand processing factors on the development of proventriculus and occurrence ofproventriculitis, in order to exploring the mainly cause of proventriculitis andapproaching a method for prevention and cure. The main contents of this study are asfollows:The first experiment was conducted to study the effects of feed form and nutrientlevel on the development of proventriculus of white feathe meat broilers, and evaluatetheir relationship with proventriculus development and proventriculitis occurrence. Atotal of960one-day-old male Ross308broiler chickens were randomly assigned to4groups with8replicates per group，and30chicks with per replicate. broilers in4groups were fed on normal nutrient level+pellet diet, normal nutrient level+mash diet,low nutrient level+mash diet and low nutrient level+pellet diet, respectively. Theper-experiment lasted for14days, and the experiment lasted for21days. The resultsshowed that nutrient level had no significant effect on the development ofproventriculus（P<0.05）and feed form had significant effect on the development ofproventriculus（P<0.05）. Pelleted diet significantly improved the average daily gain（ADG）（P<0.05）, as well induced the dysplasia and inflammatory of proventriculus.Broilers fed mash diet had significantly lower ADG than that of pelleted diet （P<0.05）, but had better proventriculus development and less inflammatory（P<0.05）. Infectious bronchitis virus was not detected in each group. Pathematologyresults showed that development of proventriculus of broilers fed with mash diet wasnormal, while inflammatory of proventriculus was found of broilers fed with pelleteddiet, also the structure of proventriculus papillae was abnormal. In conclusion，mashdiet has a positive effect on the development of proventriculus, while pelleted dietmay cause the augmentation and inflammatory of proventriculus. Nutrient level hasno significant effect on the development of proventriculus..The second experiment was conducted to study the effect of feed form andparticle size on development of proventriculus of fast large white feather broilers, andevaluate their relationship with proventriculus development and proventriculitisoccurrence. A total of1080one-day-old male Ross308broilers were randomlyassigned to6groups with6replicates per group,30chicks with each replicate. Threedifferent sieve pore sizes (2.0mm,5.0mm,8.0mm) and two different feed forms(mashdiet vs pellet diet) were selected to study the effect of particle sizes of broiler pelletfeed and mash feed. There are three phases in this experiment (d1-d21, d22-d32,d33-d40). The result showed that broiler fed coarse particle size diets had higer BW,ADFI and ADG during the start phase, and FCR during grower phase. Coarse particlesize diets decreased significantly unsplit and split proventriculus width, increased thethickness of the glandular stomach muscular, nipple structural integrity and villuslength, reduced inflammatory infiltration， relaxation and swelling of mucosamuscular layer in glandular stomach. Mash diets significantly improved gizzardweight, gizzard index, and decreased proventriculus/gizzard ratio significantly(P<0.05). Higher ADG and ADFI were observed (P<0.05) for birds fed pellet dietsduring start phase, growing phase and the whole period. Pellet diets increased unsplitand split width of proventriculus and isthmus, and reduced the volume of gizzard.With particle size increased, split proventriculus and isthmus width decreasedsignificantly (P<0.05) and the development of proventriculus and the structure ofproventriculus papillae was tended to be normal. Infectious bronchitis virus was notdetected in each group. In conclusion, nutrient level has no significant effect on the development ofproventriculus; mash diets and coarse particle size has better effect on thedevelopment of proventriculus, while pelleted diets or fine particle size may cause theaugmentation and inflammatory of proventriculus.