Effect of Essential Oils on the Oxyntopeptic Cells and Somatostatin and Ghrelin Immunoreactive Cells in the European Sea Bass (Dicentrarchus labrax) Gastric Mucosa

The current work was designed to assess the effect of feed supplemented with essential oils (EOs) on the histological features in sea bass’s gastric mucosa. Fish were fed three diets: control diet (CTR), HERBAL MIX® made with natural EOs (N-EOs), or HERBAL MIX® made with artificial EOs obtained by synthesis (S-EOs) during a 117-day feeding trial. Thereafter, the oxyntopeptic cells (OPs) and the ghrelin (GHR) and somatostatin (SOM) enteroendocrine cells (EECs) in the gastric mucosa were evaluated. The Na+K+-ATPase antibody was used to label OPs, while, for the EECs, anti-SOM and anti-GHR antibody were used. The highest density of OP immunoreactive (IR) area was in the CTR group (0.66 mm2 ± 0.1). The OP-IR area was reduced in the N-EO diet group (0.22 mm2 ± 1; CTR vs. N-EOs, p < 0.005), while in the S-EO diet group (0.39 mm2 ± 1) a trend was observed. We observed an increase of the number of SOM-IR cells in the N-EO diet (15.6 ± 4.2) compared to that in the CTR (11.8 ± 3.7) (N-EOs vs. CTR; p < 0.05), but not in the S-EOs diet. These observations will provide a basis to advance current knowledge on the anatomy and digestive physiology of this species in relation to pro-heath feeds.

Nutrition and Digestive Physiology of the Broiler Chick: State of the Art and Outlook

Because the intestine is the primary nutrient supply organ, early development of digestive function in newly hatched chick will enable it to better utilize nutrients, grow efficiently, and achieve the genetic potential of contemporary broilers. Published data on the growth and digestive function of the gastrointestinal tract in neonatal poultry were reviewed. Several potential strategies to improve digestive tract growth and function in newly hatched chick are available and the options include breeder nutrition, in ovo feeding, early access to feed and water, special pre-starter diets, judicious use of feed additives, and early programming.

Molecular diet studies of water mites reveal prey biodiversity

Water mites are diverse aquatic invertebrates that provide potentially important ecosystem and economic services as bioindicators and mosquito biocontrol; however, little is known about water mite digestive physiology, including their diet in nature. Water mites, much like their spider relatives, liquefy their prey upon consumption. This results in the absence of morphologically identifiable prey in water mite mid-gut. Previous studies have reported associations in the field of water mites with presumed prey and laboratory observations of water mites feeding on specific organisms offered for ingestion; however, the present work aims to determine what water mites have ingested in nature based on molecular studies of gut contents from freshly collected organisms from the field. To elucidate water mite prey, we used next-generation sequencing to detect diverse cytochrome oxidase I DNA barcode sequences of putative prey in the guts of 54 specimens comprising two species of Lebertia and a few specimens of Arrenurus (2) and Limnesia (1). To our knowledge this is the first molecular study of the diets of water mites as they feed in nature. While the presence of chironomid DNA confirmed previous observations of midge larvae as part of the diets of Lebertia, we also found the DNA of diverse organisms in all four species of water mites, including the DNA of mosquitoes in 6 specimens of Lebertia and a large number of previously unknown prey, especially from oligochaete worms. These studies thereby reveal a greater diversity of prey and a potentially broader significance than previously appreciated for water mites in aquatic food webs. Molecular studies like this can detect water mite predators of mosquito larvae and add knowledge of water mite predatory contributions to freshwater food webs.

Comparative Study of Endogenous Ileal Amino Acid Flow and Digestive Physiology to Nitrogen-Free Diets with Differing Ratios of Dextrose to Corn Starch in Broiler Chickens

Determination of ileal endogenous amino acids (IEAAs) is necessary for the calculation of standardized ileal amino acid digestibility. This experiment was conducted to compare the response of amino acids composition of IEAAs of broilers, and digestive physiology fed the nitrogen-free diet (NFD) formulated with different ratios of dextrose to corn starch (D/CS). 28d-old broiler chickens (n = 210) with similar body weight were allocated to 5 treatment groups, including a control group (CT, basal diet, normal level of protein) and four NFD groups for a 3-days trial, designated as A (D/CS = 1.00), B (D/CS = 0.60), C (D/CS = 0.33), and D (D/CS = 0.14). The results showed that NFD significantly reduced serum IGF-1, albumin and uric acid levels when compared with the control (P < 0.05). A higher ratio of D/CS (1.00 and 0.60) increased Asp, Thr, Ser, Glu, Gly, Ala, Val, Ile, Leu, His, Tyr, Arg, and Pro contents of IEAAs when compared with the ratio of 0.33 and 0.14 (P < 0.05). Moreover, ileal DM digestibility and digestive enzyme increased with an increasing ratio of dextrose to corn starch (P < 0.001). The number of ileal goblet cells and the gene expression of Mucin 2 were higher in group A (D/CS=1.00) than in group C (D/CS = 0.33) and the control (P < 0.05). It was further observed that NFD indeed reshaped the gut microbiota, characterized by lower Bacteroidetes, a significantly increased proportion of Proteobacteria, and decreased microbial diversity (P < 0.05).Our results indicate that the chicken fed NFD were accompanied by huge digestive physiological alterations, presenting with malnutrition and accumulation of Proteobacteria in the gut. Different proportions of dextrose and starch directly affect the basal IEAAs of broiler chickens. A higher proportion of dextrose (D/CS = 1 and 0.6) in NFD increase IEAAs by promoting secretion of digestive enzyme and mucin. But the excessive proportion of starch is unsuitable for the chicken to digest NFD (D/CS = 0.14). Therefore, we suggest the ratio of dextrose to corn starch in NFD at 0.33 might be more appropriate to detect IEAAs of broiler chickens.

A comparative study of learning outcomes between video-based and traditional lecture-based teaching in physiology

Background: -Video-based teaching, a distance learning tools is widely beingused in the present COVID-19 pandemic. Present study compares cognitive and affective domains learning outcomes between traditional and video-based physiology lecture. Methods and material: -A total of 25female students of Applied Medical College, Prince Sattam bin Abdul Aziz University, kingdom of Saudi Arabia during 2019 were selected for the study. Physiology course consist of 45 credit hours in a fifteen-week semester. Students were evaluated by various methods for different levels of cognitive and affective domains between traditional method of endocrine physiology lecture session and video-based digestive physiology lecture session. Marks obtained by each student in all the assessment methods of cognitive and affective domains were calculated to get a total mean score and expressed in percentage and compared between the traditional and video-based physiology lecture. Results: -The total mean score for all the assessment methods of the cognitive domains in the digestive physiology lecture with video was 70% and endocrine lecture without video was 50%.The total mean score for affective domain in the digestive physiology lecture with video was 80% and endocrine lecture without video was 50%.Cognitive domain show no major difference between traditional endocrine physiology and video-based digestive physiology lecture, while student performance was good for affective domain in the lecture supported by video. Conclusion: -Video-based teaching helps the learner to achieve objectives of the different levels of affective domain compared to cognitive domain as well as compared to traditional lecture with no video. Bangladesh Journal of Medical Science Vol.20(4) 2021 p.833-839