Small intestinal mucosal cells in piglets fed with probiotic and zinc: a qualitative and quantitative microanatomical study

Abstract

Background: Probiotics and zinc are commonly used and beneficial in pig production. This work aimed to assess the effects of probiotic and zinc on the mucosal cells of the small intestine in respect to digestive capacity and immunity in pre and post-weaned piglets. Materials and methods: Eighteen LWY piglets were divided equally into control and treatment groups. The piglets were maintained in standard management conditions and were weaned at 28 days of age. The treatment group of piglets fed a mixture of probiotics orally @ 1.25 x 10 9 CFU/day and zinc @ 2000 ppm/day from birth to 10 days of age. At three different age-groups viz. day 20 (pre-weaning) and, day 30 and day 60 (post-weaning), the animals were sacrificed. For histomorphology, the tissue samples were processed and stained with Mayer's hematoxylin and eosin for routine study, combined PAS-Alcian blue for mucopolysaccharides and Masson-Hamperl argentaffin technique for argentaffin cells. The stained slides were observed under the microscope. The samples were processed as per the standard procedure for scanning and transmission electron microscopy. The statistical analysis of the data using the appropriate statistical tests was also conducted. Results: The mucosal epithelium of villi and crypts were lined by enterocytes, goblet cells, argentaffin cells, microfold (M-cell) cells, tuft cells and intraepithelial lymphocytes (IEL). The multipotent stem cells were located at the crypt base. The length of the enterocyte microvilli was significantly longer (P<0.05) in the treatment group of piglets. The number of different types of goblet cells and argentaffin cells was more in treated piglets irrespective of segments of intestine and age. The IEL was located in apical, nuclear and basal positions in the lining epithelium of both villus tip and base with their significant increased in the treatment group of piglets. The TEM revealed the frequent occurrence of tuft cells in the lining mucosa of the small intestine in treated piglets. Conclusions: Dietary supplementation of probiotic and zinc induced the number of different mucosal cells of villi and crypts in the small intestine that might suggest the greater absorptive capacity of nutrients and effective immunity in critical pre and post-weaned piglets.

Bioactive compounds, antibiotics and heavy metals: Effects on the intestinal structure and microbiome of monogastric animals – a non-systematic review

“…For example piglets orally receiving a mix of a probiotic (1.25 × 10 9 CFU/day) and zinc (2000 ppm/day) showed the presence of stem cells at crypt base and elongation of the enterocyte microvilli in the small intestine, which can suggest an increased capacity to absorb nutrients and efficient resistance (Kalita et al, 2021). On the other hand, weaned pigs administered 2500 ppm of zinc oxide and/or a commercial mix of benzoic acid and probiotics (Bacillus licheniformis, Bacillus subtilis and Enterococcus faecium) showed that zinc oxide administrated alone had a stronger influence on the composition of the microbiota, although the microbiota of the ceacum in both groups of piglets was dominated by Firmicutes, followed by Bacteroidetes bacteria (da Silva et al, 2021).…”

Intraepithelial lymphocytes in the pig intestine: T cell and innate lymphoid cell contributions to intestinal barrier immunity

“…IEL distributions also vary by locality within crypts and villi and in relation to luminal proximity, including location in the basement membrane, enterocyte nuclear level, or apical epithelium ( Figure 1 ). In porcine small intestine, IELs preferentially congregate to intestinal villi over crypts at up to a four-to-one ratio ( 65 – 67 , 77 , 78 , 83 , 97 , 98 ). Preferential accumulation of IELs in villi suggests IEL effector functions may involve close interactions with signals derived from the intestinal lumen, as villi are more intimately associated with the lumen compared to shielded niches of crypts.…”

“…IELs in small intestinal villi also differ in distribution across the epithelial layer in relation to luminal proximity. While the majority of IELs are located near the basement membrane, some IELs are in closer proximity to the lumen, including at the enterocyte nuclear level, apically, or even freely within the lumen ( 65 , 67 , 78 , 79 , 87 , 97 , 101 ). However, IEL detection within the free lumen must be cautiously interpreted, as technical variables of tissue processing may compromise tissue integrity.…”

“…About half of porcine small intestinal IELs contain cytoplasmic granules accompanied by prominent mitochondria, ribosomes, nuclei, and nucleoli ( 167 ) that are indicative of cytotoxic capacity and elevated metabolic/protein production. IELs with enlarged cytoplasm, granules, and prominent organelles are preferentially found in apical epithelial locations in closer proximity to the lumen, whereas the majority of total IELs are located in the basement membrane, do not have enlarged cytoplasm, and have dense, round nuclei ( 79 , 97 ). From these observations, we speculate a correlation between luminal proximity and IEL effector function, where IELs in the basement membrane are naïve or patrolling IELs that require additional activating signals to infiltrate the epithelium.…”

Lymphocyte subsets in the small intestine of piglets fed with probiotic and zinc: a qualitative and quantitative micro-anatomical study

“…In addition, zinc supplementation has been responsible for maintaining nonspecific defense mechanisms [8]. Kalita et al [9] already described the probiotic and zinc effects on the small intestinal mucosal cells in piglets.…”