الفهرس 
Probiotics and their role in poultry feedingOnly 14 pages are availabe for public view
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Abstract
The present study was carried out at the Poultry Physiology Laboratory. Department of Poultry Production, Faculty of Agriculture, Ain Shams University, during the period from December 2015 to January 2016.
The study aimed to elucidate the possible effects of prehatching in ovo administration of Lactobacillus acidophilus bacteria as a gowth promotor and immune modulator on posthatch productive performance lymphoid organs development and some physiological and histological traits of broiler chicks.
Two hundred and seventy broiler breeder eggs with an average weight of 68.61 g were obtained from a commercial broiler breeder flock (Hubbard) at 48 WOA. At the embryonic day 14 (E14), eggs were candled, so all infertile eggs and early dead embryos were identified and excluded.
At the embryonic day 17 (E17), eggs were randomly divided into six main groups, each of 40 eggs. All eggs were set under the normal incubation conditions. The first group served as control (C), while the second and third groups were used as a positive control in wich in ovo saline injected either in air cell (Sr) or in the amniotic fluid (Sm), respectively. Eggs of the 4th and 5th groups were subjected to in ovo injection with Lactobacillus bacteria at concentration of 9.8 x 109 cfu (0.1ml /egg) into air cell (Br) and the amniotic fluid (Bm), respectively. The 6th was orally inoculated (O) with the same dose of bacteria immediately posthatching.
Late embryonic mortality, hatchability percentage, post-hatching performance, carcass characteristics, some blood biochemical constituents, digestive enzymes activity and bacteria counts of the small intestine contents, of intestinal content, histomorphometric measurements of intestinal and immune lymphoid organs were estimated.
The obtained results could be summarized as follows:
1. Hatchability percentage was increased for all in ovo injection treatments except for eggs that injected with saline solution in the amnion (Sm).
2. Total embryonic mortality was reduced for eggs injected with Lactobacillus bacteria in the amnion.
3. In ovo injection of LAB did not affect chicks weight at hatch, while at two weeks of age live body weight of in ovo LAB injected chicks and oral inoculated groups showed significantly heavier body weight than the other groups.
4. There were differences in live body weight between all treatments at the end of the experimental period (5wk).
5. Feed consumption was not affected by treatments, while feed conversion ratio was significantly better at 2WOA for chicks form in ovo-air cell (Br) and amnion (Bm) groups followed by chicks from oral-inoculated (O) group.
6. The relative weight of carcass was significantly increased in the Bm injected chicks group followed by those of the control; Br injected and then the orally-inoculated chicks group.
7. The relative weight of liver was significantly increased in chicks from air-cell injected and oral inoculated (O) groups compared to the amnion injected (Bm) and the control groups.
8. In ovo injection and oral inoculation treatments had nonsignificant effect on plasma total protein, globulin and A/G ratio of broiler chicks at 35 DOA while, plasma albumin level was significantly increased for Br-injected group followed by the other treatments.
9. Plasma immunoglobulins (IgG; IgM and IgA) were not significantly influenced by all treatments.
10. Plasma cholesterol level and HDL were significantly decreased in all treatment groups compared to the control one.
11. There were significant decreased in plasma LDL level for all treatment groups compared to the control group.
12. Transaminases activity were significantly decreased in blood plasma of broiler chicks of all treatment groups than the control.
13. Insulin-like growth factor-І concentration in blood was significantly higher for chicks from Br and O groups than Bm and control groups.
14. Plasma triiodothyronine (T3) concentration was significantly increased for chicks from Br and O treatments compared with Br and control chicks groups, while plasma thyroxine (T4) level was not affected.
15. Plasma T3/T4 ratio was signifigantly higher for chicks from Br and O treatments than the other treatments.
16. The relative weight of spleen and bursa of Fabricius were not influenced by all treatments.
17. Digestive enzymes activity (lipase, trypsin and chymotrypsin) was significantly higher (trypsin and chymotrypsin) and lower (lipase)in chicks form Br, Bm and treatment group compared to control, but amylase activity was not affected.
18. Total bacteria count and total lactic acid bacteria were significantly higher in the intestinal contents of day old chicks and of 35 DOA chicks from the oral-inoculated (O) Br and Bm-in ovo injected groups compared to the control ones.
19. Total coliform bacteria count and total fecal coliform bacteria were significantly decreased by Lactobacillus treatments compared to the control chicks either at one or 35 DOA, except for fecal coliform bacterial count of day old chicks of the orally-inoculated treatment which did not differ than the control chicks.
20. Histological examination of ileum sections showed that villi height; crypts depth and villus height/crypts depth were significantly influenced by different Lactobacillus treatments compared to control chicks, however the musculosa layer was not changed.
21. Histological examination of cecum sections showed that in ovo injection and oral-inoculation of Lactobacillus acidophilus bacteria significantly improved the epithelial layer (mucosa) height and musculosa layer depth especially for Br and O treatments.
22. In ovo injection and oral inoculation of Lactobacillus bacteria improved the histological structure of spleen, as the white pulp area was dramatically increased then the red pulp area.
23. Cecal tonsils histology showed an enhancement with Lactobacillus treatments over the control sections.
from the previous results, it could be concluded that in ovo injection of broiler eggs with Lactobacillus acidophilus bacteria at the 17th day of inoculation period either into air cell or amniotic sac could be used as an effective tool for improving productive performance and immune responses of broiler chicks without negative impacts on hatchability percentage and general physiological status of growing chicks. Also, using of oral inoculation method to deliver the beneficial bacteria into day old chicks could be used as an alternative method. Our results tend to recommend in ovo injection application via air cell of eggs, which proved to be practical, easier and more safety than the other methods.