Histomorphometry and histopathology of small and large intestine of fattening Arabi lambs fed with whole branches of Albizia lebbeck

Morphological features of the gastrointestinal tract, namely the epithelial tissue and rumen papilla, villi, and crypts of the small intestine are the most important indicators for judging the digestibility capacity, metabolism, and absorption and production performance of animals in the future. Multipurpose trees such as Albizia lebbeck can be used as a source of nitrogen in ruminant diets. The foliage of these trees is used as an inexpensive source of nitrogen and also contains energy, minerals, and vitamins. Tannins, cyanides, oxalates, saponins, and trypsin inhibitors have been suggested as anti-nutritional compounds of Albizia lebbeck. High concentrations of polyphenolic compounds in plants cause tissue damage, loss of epithelial cells, microvilli erosion, and shortening of villi height, which reduces the ability to absorb nutrients. Tannins can inhibit microbial activity and inactivate extracellular endoglucanase in some fiber-digesting bacteria. Tannins can inhibit microbial activity and inactivate extracellular endoglucanase in some fiber-digesting bacteria. Therefore, the aim of this study was to investigate the histomorphometry and histopathology of small and large intestinal tissue of fattening lambs fed foliage of Albizia lebbeck as a feed containing tannins and other secondary polyphenolic compounds.

In this experiment, Twenty-four fattening Arabian male lambs with eight months old and initial body weight of 28.8±5.34 kg were used for 60 days. The experiment was performed in a completely randomized design with three treatments and eight replicates. The experimental treatments were: control diet (without Albizia lebbeck) and control + 50 and 75 percent complete branches of Albizia lebbeck replaced with alfalfa.

In the duodenum section, the villi height and crypt depth in the control treatment were higher than other treatments and were significant compared to the treatment containing 75% complete branches of the Albizia lebbeck (P <0.05). The villi width and villi area were also higher in the control treatment than other treatments (P <0.05). The thickness of the muscle layer in the treatment receiving 75% of the complete branches of the Albizia lebbeck was higher than other treatments (P <0.05). In the jejunum section, the villi height, villi width and villi area in the control treatment were higher than other treatments (P <0.05). The crypt depth in the control treatment was higher than other treatments and was significant compared to the treatment containing 50% complete branch of the Albizia lebbeck (P <0.05). The thickness of the muscle layer in the control treatment was higher than other treatments and was significant compared to the treatment containing 50% of the complete branches of Albizia lebbeck (P <0.05). In the ileum, the thickness of the muscle layer in the control treatment was higher than other treatments (P <0.05). Infiltration of inflammatory cells in the control treatment was higher in different parts of the intestine than other treatments. Feed intake, average daily gain, feed conversion ratio, and feed efficiency were not affected by experimental treatments

Compared to the control, In terms of Histopathology use of Albizia lebbeck reduced the penetration of inflammatory cells in the small intestine and large intestine; however, had no effect on feed intake and growth performance. The consumption of Albizia lebbeck is recommended in animals due to the presence of flavonoids, high levels of protein, reduce feed costs, positive tissue effects, and increase NDF digestibility.