الفهرس 
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Abstract
The present study was carried out in Maryout Research Station (32º N Latitude), 35 kilometers southwest of Alexandria that belongs to Desert Research Center. This work was conducted to test the hypothesis that sheep and goats can tolerate feed shortage under semi-arid condition and if there is a difference between sheep and goats in their ability to withstand this shortage and harsh condition. Twenty female small ruminant animals were used in the present study. Experimental animals were ten adult female Barki sheep and ten adult female Baladi goats, approximately 3-5 years of age with an average body weight of 35.26 ± 4.31 and 30.67 ± 4.29, respectively. Animals in each species were divided into two groups (5 animals each) according to the feeding levels, 50% or 100% of maintenance requirements. The present study was designed to detect the impact of feed restriction (protein and energy) on live body weight, physiological responses, blood picture and some immunological and biochemical responses of the adult female small ruminants. In addition, histological, histopathological and cell ultrastructural studies of lymph nodes, ovary and uterus were investigated to estimate some reproductive traits of both dry ewes and does.
The results could be summarized as follow:-
1. The highest averages ambient temperature was recorded in September while the lowest in November. On the other hand, the highest average relative humidity was recorded in December while the lowest was recorded in October. The highest rainfall was measured during December while the lowest was detected in September. Along the experimental period ambient temperature was higher at 02.00pm than at 08.00am while relative humidity displayed the reverse trend.
2. Results indicated that feed restriction (50% for 4 months) resulted in an insignificant decrease in the live body weight in both sheep and goats. When expressing the losses as a percentage of initial LBW, it was found that low feed intake had more deleterious effects especially on goats’ LBW where losses reached 6.28% and 8.45% for ewes and does, respectively.
3. Skin temperature was significantly decreased while rectal and coat temperatures were insignificantly influenced by feed restriction. Diurnal in temperatures measured were negligible due to temperate climate prevailing during experimental period. In addition, there were no significant differences between the infrared radiations of all animals at the same times. Respiration rates did not show diurnal change but increased in both species due to higher intake. However, all values of RR were in the normal range.
4. The RBCs values in sheep and goats were decreased significantly by restricted feeding. The percentage decreases were 8.63 and 15.52% in sheep and goats, respectively. Haematocrit (Hit %) and platelets count decreased (P<0.05) by feed restriction in sheep and goats. The decrease in Hit % was more apparent in does being 11.14%, while was only 6.69% in ewes. The mean corpuscular volume (MCV) was not influenced by feed restriction. Both mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration percentage (MCHC %) in sheep were not significantly affected by the change in feeding levels. Meanwhile, goats fed 50% showed significant higher MCH and MCHC% values than those fed 100%. The present study claimed that feed restriction reversely affected platelets synthesis.
5. Present results indicated that WBCs count significantly (P<0.05) decreased in sheep and insignificantly increased in goats in response to feed restriction. There is no marked change in the counts of Lymphocytes, Neutrophils, Eosinophils and Basophils due to feed shortage in both sheep and goats. Monocytes concentration was increased in sheep, but significantly decreased in goats in response to four months feed restriction.
6. Changes in plasma total proteins (TP) as affected by feed restriction showed that the decreased significantly with the decrease of feeding level. Albumin content is not affected by feeding level. On the other hand, feed restriction decreased serum globulin in both species. Under the two levels of nutrition TP began to decline after 8 weeks, then return to its original level after 14 weeks. However, goats received 50% of their maintenance requirements could not attain their TP level before treatment.
7. Plasma glucose in sheep increased significantly by feed restriction while that of goats was not affected. Only in sheep, lactate dehydrogenase decreased (P<0.05) by feed restriction. While plasma glucose of sheep had stable level throughout the experimental period, that level in goats increased steadily from the 4th week to reach its level at 14 – 16th weeks. Lactate dehydrogenase fluctuated in both species but near the end of experimental period (14th -16th week) it increased in animals exposed to restricted feeding.
8. Plasma total lipids (TL), triglyceride, cholesterol and high and low density lipoproteins tended to increase in response to feed restriction in sheep while in goats similar trend was observed except for cholesterol and lipoproteins which were reduced in response to feed restriction. Goats under the two nutrition levels increased TL early from the 4th week of treatment. The increase was apparent in does exposed to feed restriction. This confirms the concept that goats utilized all their energy resources to cope with feed deficiency and cold stress. Sheep showed increased TL later at the week 12 of treatment, which reflects the importance of fat tail in providing energy at need.
9. The evaluation of liver enzymes like Alanine transferase (ALT), Aspartate transferase (AST), Gamma glutamyl transferase (GGT) and Alkaline phosphatase (ALKP) revealed that different enzymes increased by decreased feeding levels in sheep and goats except the ALk.P of sheep which decreased significantly by decreasing feeding level.
10. Blood urea and urea nitrogen were significantly increased in sheep and goats due to feed restriction. Feeding level had no significant effect on the mean values of creatinine. Serum urea in animals received low level of nutrition increased from the beginning of treatment to reach the highest level in the 8th week, then declined sharply in the 10th week, then increased again but did not reach the level of week 8.
11. Feed restriction decreased (P<0.05) serum iron and total iron binding capacity in sheep. Also, unbound iron binding capacity and transferrin saturation in sheep showed slight decrease. Sheep had low level of feeding seemed to be exposed to hypochromic anemia.
12. In sheep Na, K and P increased (P<0.05), while Ca decreased (P<0.05) by restricted feeding. In goats K, Ca and P increased (P<0.05) by restricted feeding while Na was not affected. Feed restriction only decreased serum copper and magnesium concentration in both sheep and goats while manganese and zinc were not significantly influenced, or being elevated.
13. Immunoglobulin A (IgA) decreased in both species by restricted feeding but significantly only in sheep. Immunoglobulins G and M increased (P<0.05) in both species duo to feed restriction. Low level feeding resulted in insignificant decrease of complement 3 in sheep and goats. Complement 4 increased in both species by restricted feeding but significantly only in female goats.
14. Restricted feeding resulted in significant increase in 6 cytokines in both species which are IL-1β; IL-1; IL-4; IL-6; IL-8 and IL-12. There was no effect due to feed restriction on TNF-α, IL-1α and IL-10. Female goats showed higher percentage increase than female sheep in IL-6 and IL-8, while they showed the same percentage increase in IL-1β, IL-1, IL-4 and IL-12. The present results indicated that feed restriction might enhance humoral and cellular immunity, but in different manners, in sheep and goats.
15. Feed restriction decreased average number of estrus cycles in both species. Feed restriction affected reproductive performance of sheep more than goats as exhibited by hormonal changes during estrous cycle.
16. Histology and cell ultrastructure:-
a) Histological and ultrastructural studies indicated that feed restriction had negatively affected lymph nodes and ovarian and uterine tissues as indicated by massively necrotic ovarian follicles, hyperplasia of uterine glandular cells, and severely necrotic follicles in the lymph nodes.
b) In sheep the histopathology of the lymph nodes from control group revealed apparently normal lymphoid follicles, while, those from restricted feeding group showed severely necrotic follicles. Ovaries from restricted feeding group showed necrosed ovarian follicles. Uterus from restricted feeding sheep group showed degenerated glandular layer of endometrium with vasculitis.
c) In goats, the lymph node of the control animals showed normal lymphoid follicles, while those of does subjected to restricted feeding showed moderately necrotic follicles. Ovaries from restricted feeding group indicated lightly necrosed ovarian follicles. The restricted feeding goats showed inactive endometrium.
d) The electron microscopic examination of the lymphocytes showed irregular, oval, and indented nucleus with patchy heterochromatin near the nuclear envelope. An abundant amount of cytoplasm surrounded the nucleus. Large, oval to rounded mitochondria were scattered in the cytoplasm. A small Golgi apparatus with a few membrane profiles and a large amount of ribosomes were present in the cytoplasm. A few profiles of rough endoplasmic reticulum were noticed.
e) The electron microscopic examination showed oval-shaped macrophages, observed in the medullary sinuses, had surface projections. The nucleus of the macro¬phage was oval, and had a shallow indentation on one pole. The heterochromatin formed a very narrow band at the nuclear envelope. No nucleoli were present. These cells showed mitochondria, rough endoplasmic reticulum lysosomes. As well as these cells showed pseudopodia.
f) In the Electron microscopic examination the ovary showed degenerated oocytes surrounded with phagocytic cells.
It could be concluded from this study that mature sheep and goats could not tolerate feed restriction (50% from maintenance requirements) under temperate to cold ambient temperatures. This was indicated by the decrease in body weight, RBCs, Hit %, HB and platelets count. Feed restriction decreased globulin besides enhancing humoral and cellular immunity indicating occurrence of inflammation. Moreover, lymph nodes were reversely affected which in turn reduced the synthesis and activation of phagocytic and T-cells. Moreover, reproductive activities were decreased specially in ewes through alteration in estrous cycle characteristics and sexual hormones, in addition to bad effects on ovarian and uterine tissues.
While does were inversely affected by feed restriction mainly through obvious decrease in LBW, ewes showed signs of seizing reproduction. However, more investigations are needed including more nutrition levels under different seasons.