Efficacy of essential oils combination on performance, ileal bacterial counts, intestinal histology and immunocompetence of laying hens fed alternative lipid sources

Abstract

This study was carried out to assess the effects of a blend of herbal essential oils (namely Thymus vulgaris, Mentha piperita, Rosmarinus offisinalis and Anethum graveolens) and different dietary lipid sources on the performance, ileal bacterial enumeration, intestinal histological alterations and immune responses in laying hens. For this purpose, a total of 150 laying hens were randomly allocated to six experimental treatments with five replicates of five birds each. Dietary treatments consisted of three levels of a mixture of essential oils (0, 100 and 200 mg/kg) and two sources of lipid (soybean oil and fish oil containing different ratios of n-6 to n-3 fatty acids) fed to the animals during an 80-days feeding trial. Findings indicated that dietary administration of fish oil not only increased significantly the spleen relative weight (p < 0.01) and the antibody titre against Newcastle virus (p < 0.05) but also led to reductions in liver relative weight (p < 0.05) and feed conversion ratio (p < 0.05). Moreover, the mixture of herbal essential oils brought about declines in hepatic relative weight, heterophile to lymphocyte ratio (p < 0.05) and intestinal pathogen populations (p < 0.01). Mention must also be made of the improvements it made in spleen weight (p < 0.01), antibody titres against SRBC (p < 0.01) and Newcastle virus (p < 0.05), villus height to crypt depth ratio (p < 0.01), goblet cell numbers (p < 0.05), lamina propria lymphatic follicle diameters (p < 0.01) and feed conversion ratio (p = 0.06). It may be claimed that the enhancements observed in the performance of laying hens fed fish oil and 200 mg/kg of the blend of essential oils could have potentially been associated with improved intestinal health indices as well as cellular and humoral immune responses.

Effects of oregano (Lippia origanoides) essential oil supplementation on the performance, egg quality, and intestinal morphometry of Isa Brown laying hens

“…By contrast, while Wang et al [33] observed a significant increase in the height of the villi in the ileum of hens supplemented with 300 ppm of essential oils and organic acids, they did not observe any such differences in the duodenum or jejunum or in the depth of the crypts or the villus height:crypt depth ratio of the intestinal regions. However, Mousavi et al [44] showed that supplementation with 100 or 200 ppm of a mixture of essential oils that contained thymol as one of the active ingredients resulted in an increase in the villus height and the villus height:crypt depth ratio in the jejunum of layers. These authors considered that the increased villus height:crypt depth ratio may have been due to an increase in the height of the villi as a result of the bioactive compounds that were present in the essential oils, as these components can induce changes in the histology of the gastrointestinal tract, the chemical composition of the digestive juices, the secretion of digestive enzymes, and the tissues related to the gastrointestinal tract, and thus can improve the digestibility of the diet leading to better growth and performance.…”

Consequences of various housing systems and dietary supplementation of thymol, carvacrol, and euganol on performance, egg quality, blood chemistry, and antioxidant parameters

“…The EO compounds can stimulate the synthesis of proteins and the immune system, protecting the cells against the oxidation process ( Moomivand et al., 2015 ). The enhancements observed in the performance of laying hens fed EOs could have potentially been associated with improved immune response ( Mousavi et al., 2018 ).…”

Use of encapsulated Bacillus subtilis and essential oils to improve antioxidant and immune status of blood and production and hatching performance of laying hens

“…(Attia et al 2015(Attia et al , 2017(Attia et al , 2019Li et al 2018;Teixeira et al 2019;Krauze et al 2020). Additionally, it has been shown that BS or EO supplementation can improve gut morphology, increase the population of beneficial gut microflora, thereby increasing the efficiency of nutrient utilisation (Mousavi et al 2018). However, Abdel-Wareth (2016) reported that the effects of thymol and synbiotic on the performance of Hy-Line Brown hens and found that there was not a positive effect.…”