Effect of quercetin administration during the first two weeks post-weaning on the development of non-alcoholic fatty liver disease and dyslipidaemia in Sprague Dawley rats fed a high fructose diet

Hepatic steatosis and dyslipidaemia are associated with excessive fructose consumption. We investigated the effect of quercetin intake during the early pre-weaning period on metabolic dysfunction caused by a high fructose diet. Sprague Dawley rats, 21-day-old, were weaned onto standard rat chow and randomly allocated to four groups which either water or 20% fructose solution to drink with or without quercetin (100 mg/kg body mass). Quercetin was administered for two weeks. Thereafter, rats continued on their respective diets for six weeks without quercetin. Terminally, serum triglyceride concentrations were not significantly different (p > 0.05) between males across groups. However, females receiving quercetin alone had lower serum triglyceride levels than those receiving fructose (p < 0.01). Quercetin increased the incidence of hepatic steatosis in female rats. Quercetin intake in the immediate post-weaning period may prevent hypertriglyceridemia. However, female rats receiving quercetin alone are predisposed to hepatic steatosis associated with a high fructose diet.

A 3D-Printed Biomaterial Scaffold Reinforced with Inorganic Fillers for Bone Tissue Engineering: In Vitro Assessment and In Vivo Animal Studies

This research aimed to substantiate the potential practicality of utilizing a matrix-like platform, a novel 3D-printed biomaterial scaffold, to enhance and guide host cells' growth for bone tissue regeneration. The 3D biomaterial scaffold was successfully printed using a 3D Bioplotter^® (EnvisionTEC, GmBH) and characterized. Osteoblast-like MG63 cells were utilized to culture the novel printed scaffold over a period of 1, 3, and 7 days. Cell adhesion and surface morphology were examined using scanning electron microscopy (SEM) and optical microscopy, while cell viability was determined using MTS assay and cell proliferation was evaluated using a Leica microsystem (Leica MZ10 F). The 3D-printed biomaterial scaffold exhibited essential biomineral trace elements that are significant for biological bone (e.g., Ca-P) and were confirmed through energy-dispersive X-ray (EDX) analysis. The microscopy analyses revealed that the osteoblast-like MG63 cells were attached to the printed scaffold surface. The viability of cultured cells on the control and printed scaffold increased over time (p < 0.05); however, on respective days (1, 3, and 7 days), the viability of cultured cells between the two groups was not significantly different (p > 0.05). The protein (human BMP-7, also known as growth factor) was successfully attached to the surface of the 3D-printed biomaterial scaffold as an initiator of osteogenesis in the site of the induced bone defect. An in vivo study was conducted to substantiate if the novel printed scaffold properties were engineered adequately to mimic the bone regeneration cascade using an induced rabbit critical-sized nasal bone defect. The novel printed scaffold provided a potential pro-regenerative platform, rich in mechanical, topographical, and biological cues to guide and activate host cells toward functional regeneration. The histological studies revealed that there was progress in new bone formation, especially at week 8 of the study, in all induced bone defects. In conclusion, the protein (human BMP-7)-embedded scaffolds showed higher regenerative bone formation potential (week 8 complete) compared to the scaffolds without protein (e.g., growth factor; BMP-7) and the control (empty defect). At 8 weeks postimplantation, protein (BMP-7) significantly promoted osteogenesis as compared to other groups. The scaffold underwent gradual degradation and replacement by new bones at 8 weeks in most defects.

β-sitosterol as an alternative to oxytetracycline: Effect on growth performance, feed intake and utilization efficiency and viscera macromorphometry of Cobb 500 broiler chickens

Antibiotics are used to fortify broiler chicken feeds as growth promoters. Chronic antibiotic use pollutes the environment and causes the development of antibiotic resistance. Natural alternatives that mimic the properties of antibiotics, without causing health and environmental challenges are required. β-sitosterol has antimicrobial, antioxidant, digestive and immune system modulating and growth stimulating activities. We evaluated its potential to replace oxytetracycline as a growth-promoter in broiler chicken feeds. Two hundred and forty, one-day-old Cobb 500 broiler chicks were randomly allocated to four diets where β-sitosterol replaced oxytetracycline at 0 mg/kg (control; fortified with 50 mg/kg oxytetracycline), 500 mg/kg, 1000 mg/kg and 1500 mg/kg (w/w) feed and fed for 6 weeks: 2 weeks for each growth phase. Each diet was replicated thrice with 20 chicks per replicate. Initial, weekly and terminal body mass (TBM) and daily feed intake (FI) were measured. Body mass gain (BMG), average daily gain (ADG) and feed conversion ratio were computed. Terminally, the chickens were fasted for 4 h then slaughtered and dressed. Gastrointestinal tract (GIT) and GIT accessory viscera masses and small and large intestine lengths were measured. Dietary fortification with β-sitosterol had similar effects (P > 0.05) to oxytetracycline on the chickens' TBM, BMG, ADG, FI and utilisation efficiency and GIT organ macromorphometry. In conclusion, β-sitosterol can replace oxytetracycline in Cobb 500 broiler chicken feeds without compromising growth performance, feed intake and utilisation efficiency and GIT organ growth and development.

Neonatal Oral Administration of Chrysin Prevents Long-Term Development of Non-Alcoholic Fatty Liver Disease in a Sexually Dimorphic Manner in Fructose Nurtured Sprague Dawley Rats

High-fructose diets are linked with the development of non-alcoholic fatty liver disease (NAFLD), the management of which is a burden to society. Interventions with phytochemicals in the early postnatal period may prevent fructose-induced NAFLD later in adulthood. We investigated the protective potential of chrysin against fructose-induced NAFLD. Four-day-old male and female suckling Sprague Dawley rats (N = 112) were randomly grouped and orally gavaged daily with distilled water (negative Control-Cn + W), chrysin(Chr-100 mg/kg), fructose-solution (Fr-20% w/v), and Chr + Fr between postnatal day (PND) 4 and 21 and then weaned onto normal rat chow and plain drinking water to PND 55. From PND 56 to 130, half of the rats continued on plain water, and the rest had Fr as drinking fluid. Terminally, the liver tissue was collected, and the lipid content was determined and histologically assessed for NAFLD. Dietary Fr induced an increased hepatic lipid content (p = 0.0001 vs. Cn + W) both sexes, and it was only attenuated by neonatal Chr in female rats (p < 0.05). Histologically, there was increased microvesicular steatosis (p = 0.0001 vs. Cn + W) in both sexes, and it was prevented by neonatal Chr (p > 0.05). Fr caused macrovesicular steatosis (p = 0.01 vs. Cn + W) in females only, and chrysin did not prevent it (p > 0.05). Fr induced hepatocellular hypertrophy, and inflammation was observed in females only (p = 0.01 vs. Cn + W), and this was prevented by Chr (p > 0.05). The collagen area fraction was increased by Fr (p = 0.02 (males) and p = 0.04 (females) vs. Cn + W, respectively; however, chrysin did not prevent this (p > 0.05). Neonatal chrysin prevented some of the deleterious effects of the high-fructose diet on the liver, suggesting that chrysin should be further explored as a strategic prophylactic neonatal intervention against high-fructose-diet-induced NAFLD.

Neonatal administration of zingerone prevents the subsequent development of high dietary fructose-induced early features of nephropathy in rats

Excessive consumption of fructose-rich diets in early life stages increases the risk for developing nephropathy in adulthood. We investigated the potential preventive effects of neonatally administered zingerone on the development of dietary fructose-induced nephropathy. Four-day-old suckling male and female rat pups were orally gavaged (10 ml/kg) with: distilled water (Con group), 20% fructose solution (Fru group), 20% fructose solution + 40 mg/kg zingerone in distilled water (ZFru group), or 40 mg/kg of zingerone (Zgr group) for 14 days. Thereafter, Con and Zgr groups continued on plain drinking water while Fru and ZFru groups drank 20% fructose solution ad libitum for 10 weeks. The Fru group had significantly increased plasma concentration of the renal injury marker kidney injury molecule one (KIM-1) and decreased glomerular urinary space area compared to the controls in both sexes (p < 0.05). These alterations were prevented by neonatally administered zingerone. Zingerone administration neonatally is a potential prophylaxis for longterm high-fructose diet-induced nephropathy.

Neonatal zingerone protects against the development of high-fructose diet-induced metabolic syndrome in adult Sprague-Dawley rats

During the early postnatal period, dietary manipulations can alter the developmental trajectory of the growing offspring, causing beneficial or adverse health outcomes later in adult life. We investigated the potential preventive effects of neonatal zingerone intake on the development of fructose-induced metabolic derangements in rats.Four-day old male and female Sprague-Dawley rat pups (n = 79) were randomly grouped and administered: 10 ml/kg body weight (bwt) of distilled water (W), 10 ml/kg bwt 20% fructose solution (FS), 10 ml/kg bwt fructose solution + 40 mg/kg bwt of zingerone in distilled water (ZF) or 40 mg/kg bwt of zingerone in distilled water (ZW) pre-weaning. After weaning, W and ZW continued on unlimited tap water, while FS and ZF continued on unlimited fructose solution for 10 weeks. Body mass and food and fluid intake were evaluated, plasma was collected for metabolic assays and visceral fat was quantified.Food intake was decreased, fructose and overall caloric intake were increased due to fructose feeding in both sexes (P < 0.05). When compared with the controls, the high-fructose diet significantly raised the terminal body masses of females (P < 0.0001), concentrations of triglycerides, total cholesterol, LDL-c, TG:HDL-c ratio and visceral fat mass relative to bwt in both sexes (P < 0.05). Zingerone prevented (P < 0.05) the fructose-induced increase in body mass (females) and hypercholesterolemia (both sexes). Levels of HDL-c, glycaemic parameters and adiponectin were not affected by the interventions (P > 0.05). Sex-related differences were observed in food, fluid and caloric intake, terminal mass, cholesterol subtypes and visceral fat percentage (P < 0.05).Zingerone could be used strategically in the neonatal phase as a prophylatic management of high-fructose diet-induced metabolic syndrome.

Administration of ursolic acid to new-born pups prevents dietary fructose-induced non-alcoholic fatty liver disease in Sprague Dawley rats

Overconsumption of fructose time dependently induces the development of non-alcoholic fatty liver disease (NAFLD). We investigated whether ursolic acid (UA) intake by new-born rats would protect against fructose-induced NAFLD. One hundred and seven male and female Sprague Dawley rat pups were randomly grouped and gavaged (10 ml/kg body weight) with either 0.5% dimethylsulphoxide (vehicle control), 0.05% UA, 50% fructose mixed with UA (0.05%) or 50% fructose alone, from postnatal day 6 (P6) to P20. Post-weaning (P21-P69), the rats received normal rat chow (NRC) and water to drink. On P70, the rats in each group were continued on water or 20% fructose to drink, as a secondary high fructose diet during adulthood. After 8 weeks, body mass, food and fluid intake, circulating metabolites, visceral adiposity, surrogate markers of liver function and indices of NAFLD were determined. Food intake was reduced as a result of fructose feeding in both male and female rats (p < 0.0001). Fructose consumption in adulthood significantly increased fluid intake and visceral adiposity in female rats (p < 0.05) and had no apparent effects in male rats (p > 0.05). In both sexes of rats, fructose had no significant (p > 0.05) effects on body mass, circulating metabolites, total calorie intake and surrogate markers of hepatic function. Fructose consumption in both early life and adulthood in female rats promoted hepatic lipid accumulation (p < 0.001), hypertrophy, microvesicular and macrovesicular steatosis (p < 0.05). Early-life UA intake significantly (p < 0.001) reduced fructose-induced hepatic lipid accumulation in both male and female rats. Administration of UA during periods of developmental plasticity shows prophylactic potential against dietary fructose-induced NAFLD.

The Potential Therapeutic Value of Medicinal Plants in the Management of Metabolic Disorders

Metabolic syndrome (MetS) is a prevalent, multifactorial and complex disease that is associated with an increased risk of developing diabetes and other major cardiovascular complications. The rise in the global prevalence of MetS has been attributed to genetic, epigenetic, and environmental factors. The adoption of sedentary lifestyles that are characterized by low physical activity and the consumption of high-energy diets contributes to MetS development. Current management criteria for MetS risk factors involve changes in lifestyle and the use of pharmacological agents that target specific biochemical pathways involved in the metabolism of nutrients. Pharmaceutical drugs are usually expensive and are associated with several undesirable side effects. Alternative management strategies of MetS risk factors involve the use of medicinal plants that are considered to have multiple therapeutic targets and are easily accessible. Medicinal plants contain several different biologically active compounds that provide health benefits. The impact of phytochemicals present in local medicinal plants on sustainable health and well-being of individuals has been studied for many years and found to involve a plethora of complex biochemical, metabolic, and physiological mechanisms. While some of these phytochemicals are the basis of mainstream prescribed drugs (e.g., metformin, reserpine, quinine, and salicin), there is a need to identify more medicinal plants that can be used for the management of components of MetS and to describe their possible mechanisms of action. In this review, we assess the potential health benefits of South African ethnomedicinal plants in protecting against the development of health outcomes associated with MetS. We aim to provide the state of the current knowledge on the use of medicinal plants and their therapeutically important phytochemicals by discussing the current trends, with critical examples from recent primary references of how medicinal plants are being used in South African rural and urban communities.

The long-term protective effects of neonatal administration of curcumin against nonalcoholic steatohepatitis in high-fructose-fed adolescent rats

There is an increased prevalence of nonalcoholic steatohepatitis (NASH) in adolescents. The suckling period is developmentally plastic, affecting later health outcomes. We investigated whether neonatal administration of curcumin would provide protection against the development of NASH later in adolescence in rats fed a high-fructose diet. From postnatal day (PN) 6 to PN 21, the pups (N = 128) were allocated to four groups and orally gavaged daily with either 0.5% dimethyl sulfoxide solution (vehicle control), curcumin (500 mg·kg^-1 ), fructose (20%, w/v) or curcumin and fructose combined. All the pups were weaned and half the rats in each group had tap water, whereas the other received fructose (20%) as their drinking fluid ad libitum for 6 weeks. The rats' liver NASH scores, lipid content, and RNA gene expression ratios of AMPKα and TNFα were determined. Hepatic lipid content was similar across the treatment groups in the males (P > 0.05, ANOVA). In the females, the hepatic lipid content in the treatment groups ranged from 2.7 to 4.3%. The livers of male and female rats that had fructose either as neonates and/or postweaning had significantly marked inflammation (P = 0.0112, Kruskal-Wallis) and fibrosis (P < 0.0001, ANOVA) which were attenuated by curcumin. The hepatic gene expression ratios for AMPKα in both sexes were significantly downregulated (P < 0.0001, ANOVA), whereas the expression ratios of TNFα were significantly upregulated (P < 0.0001) in rats fed a high-fructose diet pre and/or postweaning compared to the other groups. Neonatal curcumin administration is a potential natural pharmacological candidate for the prevention of NASH.

β-Sitosterol mitigates the development of high-fructose diet-induced nonalcoholic fatty liver disease in growing male Sprague–Dawley rats

Fructose contributes to the development of nonalcoholic fatty liver disease (NAFLD). β-Sitosterol (Bst), a naturally occurring phytosterol, has antihyperlipidaemic and hepatoprotective properties. This study interrogated the potential protective effect of β-sitosterol against NAFLD in growing rats fed a high-fructose diet, modelling children fed obesogenic diets. Forty-four 21 day old male rat pups were randomly allocated to and administered the following treatments for 12 weeks: group I, standard rat chow (SRC) + plain drinking water (PW) + plain gelatine cube (PC); group II, SRC + 20% w/v fructose solution (FS) as drinking fluid + PC; group III, SRC + FS + 100 mg/kg fenofibrate in a gelatine cube; group IV, SRC + FS + 20 mg/kg β-sitosterol gelatine cube (Bst); group V, SRC + PW + Bst. Terminally, the livers were dissected out, weighed, total liver lipid content determined, and histological analyses done. Harvested plasma was used to determine the surrogate biomarkers of liver function. The high-fructose diet caused increased (p < 0.05) hepatic lipid (total) accretion (>10% liver mass), micro- and macrovesicular hepatic steatosis, and hepatic inflammation. β-Sitosterol and fenofibrate prevented the high-fructose diet-induced macrovesicular steatosis and prevented the progression of NAFLD to steatohepatitis. β-Sitosterol can prospectively be used to mitigate diet-induced NAFLD.

The potential developmental programming effect of oral curcumin on the bone health and plasma total osteocalcin of male and female rats fed a high-fructose diet during suckling and post weaning

We investigated the effect of oral curcumin, on bone health of rats fed a high-fructose diet. Suckling pups (males = 65, females = 63) were gavage with 0.5% DMSO, curcumin (500 mg/kg), fructose (20%, w/v) or a combination of curcumin and fructose daily from postnatal days 6 to 21. Then the rats were weaned onto normal rat feed for six weeks and each group was sub-divided into two subgroups: one had plain tap water and the other had fructose (20%, w/v) to drink. Blood was assayed for plasma total osteocalcin. Morphometry and radiographic bone density assessments were made on the femora and tibiae. The lengths, masses and Seedor indices of the bones were similar (p > 0.05, ANOVA) across the groups. Males that received curcumin with or without fructose during suckling and weaned onto a high-fructose diet had lower (p ≤ 0.05, ANOVA) osteocalcin concentration versus the other males. Similarly, in females rats, curcumin alone or administered with fructose resulted in lower (p ≤ 0.05, ANOVA) osteocalcin concentration versus female rats administered the vehicle control. Neonatal curcumin-induced decrease in plasma total osteocalcin concentration may predispose to adverse consequences on glucose metabolism and bone health.

Pyrogenic and neuroinflammatory properties of zymosan and its potential as an alternative to live yeast in antipyretic drug testing

Zymosan, an immunogenic cell wall extract of Saccharomyces cerevisiae has potential for use as an experimental pyrogen. However, the short-lived sickness responses noted with intraperitoneal and intra-articular administration of zymosan limits investigations on the long-term effectiveness of antipyretic drugs. Thus, there remains a need to establish an alternative route of zymosan administration that could induce long-lived fevers and inflammation. We injected male Sprague Dawley rats (250–300 g) subcutaneously with zymosan (30 or 300 mg/kg) or saline; n = 7–8. We measured core body temperature, cage activity, food intake and body mass for 24 h after injection. Blood and brain samples were collected at 2, 8, and 18 h after injection. Zymosan (300 mg/kg) induced fever, lethargy, and anorexia, which lasted for 24 h. Zymosan-induced sickness responses were accompanied by increased blood plasma levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α; activation of inflammatory transcription factors (nuclear factor (NF) for IL-6, signal transducer and activator of transcription (STAT)-3, and NF-κB) in the hypothalamus and circumventricular organs; and increased hypothalamic mRNA expression of TNF-α, IL-1β, and IL-6 and rate-limiting enzymes for prostaglandin synthesis. Our results confirm the suitability of subcutaneous administration of zymosan for screening antipyretic and anti-inflammatory drugs in rats.

The protective effect of neonatal oral administration of oleanolic acid against the subsequent development of fructose-induced metabolic dysfunction in male and female rats

BACKGROUND

Consumption of fructose-rich diets has been implicated in the increasing global prevalence of metabolic syndrome (MetS). Interventions during periods of early ontogenic developmental plasticity can cause epigenetic changes which program metabolism for positive or negative health benefits later in life. The phytochemical oleanolic acid (OA) possesses anti-diabetic and anti-obesity effects. We investigated the potential protective effects of neonatal administration of OA on the subsequent development of high fructose diet-induced metabolic dysfunction in rats.

METHOD

Male and female (N = 112) suckling rats were randomly assigned to four groups and administered orally: distilled water (DW), oleanolic acid (OA; 60 mg/kg), high-fructose solution (HF; 20% w/v) or OA + HF for 7 days. The rats were weaned onto normal commercial rat chow up to day 55. From day 56, half of the rats in each treatment group were continued on plain water and the rest on a high fructose solution as drinking fluid for 8 weeks. On day 110, the rats were subjected to an oral glucose tolerance test and then euthanased on day 112. Tissue and blood samples were collected to determine the effects of the treatments on visceral fat pad mass, fasting plasma levels of cholesterol, insulin, glucose, triglycerides, insulin resistance (HOMA-IR) and glucose tolerance.

RESULTS

Rats which consumed fructose as neonates and then later as adults (HF + F) and those which consumed fructose only in adulthood (DW + F) had significant increases in terminal body mass (females only), visceral fat mass (males and females), serum triglycerides (females only), epididymal fat (males only), fasting plasma glucose (males and females), impaired glucose metabolism (females only), β-cell dysfunction and insulin resistance (males and females) compared to the other treatment groups (P < 0.05). There were no differences in fasting serum cholesterol levels across all treatment groups in both male and female rats (P > 0.05).

CONCLUSION

We conclude that neonatal oral administration of OA during the critical window of developmental plasticity protected against the development of health outcomes associated with fructose-induced metabolic disorders in the rats.

Comparison of the histology of the skin of the Windsnyer, Kolbroek and Large White pigs

The skin is a protective barrier, and an endocrine, sensory and thermoregulatory organ. We investigated whether the skin of local pigs had beneficial anatomical traits compared to exotic pigs to withstand the increased heat loads predicted under future climate change scenarios. Full-thickness skin specimens were obtained from the dorsal interscapular, lateral thoraco-abdominal and ventral abdominal regions of intact boars (age 6-8 months) of two local breeds of pigs (Windsnyer [n = 5] and Kolbroek [n = 4]) and an exotic pig breed (Large White [n = 7]). The skin sections were stained with a one-step Mallory-Heidenhain stain and Fontana stain (melanin). Sweat gland perimeter was measured using Image J software. The Windsnyer breed had the thinnest dermis layer while the Large White had the thickest dermis layer across all the three body regions (analysis of variance [ANOVA]; p < 0.001). The Windsnyers had widely spaced dermal pegs compared to the other breeds. The Windsnyers had significantly more superficial and larger (~1 mm depth; 4.4 mm perimeter) sweat glands than the Kolbroek (~3 mm depth; 2.2 mm perimeter) and Large White (~4 mm depth; 2.0 mm perimeter) pigs (ANOVA; p < 0.001). The Windsnyers had visibly more melanin in the basal layer, the Kolbroek pigs had very little and the Large Whites had none. The functionality of the sweat glands of the Windsnyer breed needs to be established. The skin from the Windsnyer breed possesses traits that may confer a protective advantage for the increased solar radiation and ambient temperatures predicted with climate change.

Terminalia Sericea aqueous leaf extract protects growing wistar rats against fructose-induced fatty liver disease

Background Terminalia sericea (T. sericea) is traditionally used to treat stomach ailments, infections, hypertension and diabetes mellitus. Previous in vitro studies have reported that T. sericea has lipolytic properties. This study interrogated the effects of T. sericea on linear growth, development of fatty liver disease, viscera morphometry and health of growing rats fed a 12% fructose solution (FS). Methods Thirty 21-day old male Wistar rat pups were randomly allocated to five treatments: group I - plain gelatine cubes (PGC) + plain tap water (PW), group II - 12% FS + PGC, group III - gelatine cubes containing fenofibrate (Feno) at a dose of 100 mg/kg body + FS, group IV - gelatine cubes containing the low dose (100 mg/kg body mass per day) of the T. sericea extract (TsL) + FS, group V - gelatine cubes containing the high dose (400 mg/kg body mass per day) of the T. sericea extract (TsH) + FS. Following 12 weeks of feeding, the rats were fasted overnight, euthanized and plasma and viscera harvested for analysis. Results Consumption of fructose resulted in significantly increased (p<0.05) liver lipid content and caused macrovesicular steatosis. The T. sericea extracts at 400 mg/kg per day suppressed the fructose-induced liver lipid accumulation and macrovesicular steatosis similarly to 100 mg/kg per day of Feno. Conclusions These findings suggest that the aqueous T. sericea leaf extract at 400 mg/kg per day could potentially protect against fructose-induced lipid accumulation as well as macrovesicular steatosis.

Insulinotropic Effect of S-Allyl Cysteine in Rat Pups

S-Allyl cysteine (SAC) is found in garlic and has been reported to exert antidiabetic and antiobesity properties in drug-induced adult experimental models of metabolic dysfunction, but its potential beneficial effects in high-fructose diet neonatal rat models have not been determined. This study investigated the potential prophylactic effects of SAC in high-fructose diet fed suckling rat pups modelling human neonates fed a high-fructose diet. Four-day-old male (n=32) and female (n=32) Wistar rat pups, were randomly assigned to and administered the following treatment regimens daily for 15 days: group I, distilled water; group II, 20% fructose solution (FS); group III, SAC; group IV, SAC+FS. The pups' blood glucose, triglyceride, cholesterol, plasma leptin and insulin concentration, liver lipid content, and liver histology were determined at termination. In female rat pups, orally administered SAC prevented FS-induced hypoinsulinemia but significantly increased (P≤0.05) liver lipid content. Oral administration of SAC significantly increased (P≤0.05) plasma insulin concentration and homeostasis model assessment for insulin resistance in the male pups. The potential sexually dimorphic effects of SAC (insulinotropic effects in male pups and protection of female pups against fructose-induced hypoinsulinemia) suggest that SAC could be potentially exploited as an antidiabetic and insulinotropic agent. Caution should, however, be exercised in the use of SAC during suckling as it could result in excessive liver lipid accumulation and insulin resistance.

A comparison of the proximate, fibre, mineral content, amino acid and the fatty acid profile of Marula (Sclerocarya birrea caffra) nut and soyabean (Glycine max) meals

BACKGROUND

As a result of shortages and the cost of the currently utilized conventional dietary protein sources in the Sub-Saharan Africa feed industry, the chemical evaluation of available non-conventional sources for feed is imperative. One such source is Marula nut meal (a by-product of Marula oil extraction). The present study chemically characterized the nutritional composition of two differently processed Marula nut meals (MNMs) and compared them with that of solvent extracted soyabean meal (SBM).

RESULTS

The MNMs had higher dry matter, ether extract and gross energy but lower crude protein and ash contents compared to SBM. The cold press produced Marula nut meal (MNM2) had higher arginine than the hydraulic filter press produced Marula nut meal (MNM1) and SBM. The meals had similar neutral and acid detergent fibre contents. The MNMs had higher phosphorus, magnesium and copper concentrations than SBM. Although the total saturated fatty acid proportion was similar across the meals, total monounsaturated and polyunsaturated fatty acid proportions were higher in MNMs and SBM, respectively. Oleic acid was higher in MNMs than in SBM.

CONCLUSION

The low crude protein content in MNMs compared to SBM is comparable with other conventional dietary protein sources. Thus, the MNMs could be used as protein and energy feed ingredients. © 2017 Society of Chemical Industry.

Brewer's yeast is a potent inducer of fever, sickness behavior and inflammation within the brain

Brewer's yeast, derived from the yeast species Saccharomyces cerevisiae (S. cerevisiae), is commonly used for inducing pyrexia in pharmacological studies screening antipyretics in rats. Despite its widespread use, the peripheral and central inflammatory response associated with Brewer's yeast-induced fever and sickness behavior in rats has not been investigated. Thus, we injected male Sprague-Dawley rats (150-200 g) subcutaneously with a high (4 g/kg, n = 9), medium (2 g/kg, n = 5) or low (0.4 g/kg, n = 6) dose of Brewer's yeast solution or saline (0.9%, n = 6) and measured core body temperature, cage activity, food intake and body mass for six days after injection. Blood and brain samples were collected at 2, 8, 18 and 72 h after injection; n = 5-7 per time point. Brewer's yeast administration dose-dependently induced fever, lethargy, anorexia and body mass stunting that was accompanied by increased blood plasma levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α and activation of inflammatory transcription factors (nuclear factor (NF) for interleukin-6, signal transducer and activator of transcription (STAT)-3, and NF-κB)) in the hypothalamus and circumventricular organs. The increased activation of transcription factors following Brewer's yeast administration was accompanied by increased hypothalamic mRNA expression of TNF-α, IL-1β and IL-6 and rate-limiting enzymes for prostaglandin synthesis. Our results show that subcutaneous administration of S. cerevisae induces prolonged fever, anorexia and lethargy that is accompanied by a pronounced increase in the synthesis of pro-inflammatory cytokines, key prostaglandin synthesizing enzymes and transcription factors, in the periphery and brain.

Effects of Dietary <I>Ximenia caffra</I> Meal on Nutrient Intake, Digestibility, Nitrogen Balance and Growth Performance in Sprague Dawley Rats Modelling Monogastrics

BACKGROUND AND OBJECTIVE

The sub-saharan livestock feed industry depends on imported soyabean meal (SBM) as a dietary protein source in feeds thus making livestock production costly. This calls for the search and development of local dietary protein sources. Using Sprague Dawley rats to model monogastric animals, this study evaluated the potential of Ximenia caffra kernel meal (XCKM) to substitute SBM as a dietary protein source in feeds.

MATERIALS AND METHODS

Five diets were formulated wherein XCKM replaced SBM on a crude protein basis at 0, 25, 50, 75 and 100%. In the digestibility trial, 20 adult male SD rats were randomly assigned to the 5 diets. After a 12-day adaptation period feed and nutrient intake, faeces and urine output were determined over a 5-day collection period. Apparent Total Tract Digestibility (ATTD) of nutrients and nitrogen absorption and retention were determined. In the growth trial, 40 weanling male SD rats were randomly assigned to the five dietary treatments and fed for 38 days. The rats were weighed twice weekly. Following euthanasia, gastrointestinal viscera were harvested and their macro-morphometry determined. Linear growth was determined from tibiae and femora indices.

RESULTS

In adult rats dietary XCKM had no (p>0.05) effect on ATTD of nutrients. At 100% substitution of SBM, XCKM increased (p<0.05) faecal nitrogen loss while at 75% substitution level it increased (p<0.05) nitrogen retention. In growing SD rats, although dietary XCKM had no effect (p>0.05) on the terminal body and empty carcass mass and viscera macro-morphometry, at 100% SBM substitution, it significantly compromised (p<0.05) body mass gain and average daily gain. Femora and tibiae mass and seed or index significantly decreased (p<0.05) with increased dietary XCKM.

CONCLUSION

The XCKM could replace SBM as a dietary protein source in adult SD rat feeds without compromising ATTD digestibility of nutrients and nitrogen utilization thus it could be speculated that XCKM can be utilized as a dietary protein source in feeds of mature monogastrics. Caution must be exercised in using XCKM in grower rat diets as its use at higher inclusion levels compromised growth performance and long bone health.

Effects of Ficus thonningii extracts on the gastrointestinal tract and clinical biochemistry of suckling rats

BACKGROUND

Ficus thonningii is commonly used in traditional medicine across the African continent. We investigated the effects of crude Ficus thonningii extracts on growth, morphology and morphometry of the abdominal viscera and clinical biochemistry of neonatal rats.

MATERIALS AND METHODS

Forty, 6-day old Sprague Dawley rat pups were orally gavaged once daily with either low (50 mg.kg(-1) b.w) or high (500 mg.kg(-1) b.w) doses of aqueous or methanolic F. thonningii leaf extracts while the control received distilled water. After 7 days of treatment, the pups were euthanased and gross morphometric measurements of the abdominal visceral organs were recorded. Samples of the liver, caecum and proximal small intestine were processed for histology. Plasma biochemical parameters were analysed colorimetrically.

RESULTS

High methanolic doses of F. thonningii extracts exhibited trophic effects on the stomach while both aqueous and methanolic extracts had trophic effects on the ceacal mucosa of rats. No significant growth-promoting effects were observed in other visceral organs. Histological analysis revealed no mucosal damage or necrosis. Clinical biochemistry parameters were not abnormally altered. There was a significant decrease (p<0.05, ANOVA) in the plasma concentration of non-fasting glucose in the high methanolic group but triglycerides and cholesterol were unaltered.

CONCLUSION

The findings suggest that at low doses, F. thonningii extracts can be safely used without the risk of any disruption in the structural integrity of the neonatal rat GIT and function of the liver and kidneys.

Fat absorption and deposition in Japanese quail (Coturnix coturnix japonica) fed a high fat diet

Dietary fat contributes significantly to the energy requirements of poultry. Not all species are able to increase their absorptive capacity for fats in response to a high fat diet. The effects of a high fat diet (10% canola oil) on the lipid absorption and deposition in the liver, breast and thigh muscles of male and female Japanese quail were investigated. Thirty-eight Japanese quail (Coturnix coturnix japonica) were randomly divided into a high fat diet (HFD) and a standard diet (STD) group. The birds were fed the diets for seven weeks after which half of the birds were subjected to oral fat loading tests (OFLT) with plant oils containing long-chain and medium-chain triglycerides. The remaining birds were included for the lipid deposition measurements. Thereafter the birds were euthanised, blood samples were collected and liver, breast and thigh muscle lipid deposition was determined. Female quail on both diets had significantly higher plasma triglyceride concentrations (p 0.05) compared with their male counterparts. No significant differences in plasma triglyceride concentrations were observed after the OFLTs. Female quail had significantly heavier liver masses compared with the males but there was no significant difference in the liver lipid content per gram liver mass. Female quail on the HFD had higher lipid content (p 0.05) in the breast muscle compared with their male counterparts whilst male quail on the HFD had higher lipid content (p 0.05) in the thigh muscle in comparison with both males and females on the standard diet. Dietary supplementation with 10% canola oil did not alter gastrointestinal tract lipid absorption, but it caused differences between the sexes in muscle lipid accumulation, the physiological significance of which requires further investigation.

Comparative effect of cane syrup and natural honey on abdominal viscera of growing male and female rats

The high intake of refined sugars, mainly fructose has been implicated in the epidemiology of metabolic diseases in adults and children. With an aim to determine whether honey can substitute refined sugars without adverse effect, the long-term effects of natural honey and cane syrup have been compared on visceral morphology in growing rats fed from neonatal age. Honey increased the caecum and pancreas weights in male rats, which could enhance enzymatic activities of pancreas and digestive functions by intestinal microflora of caecum. Unlike honey, cane syrup caused fatty degenerations in the liver of both male and female rats. Honey enhanced intestinal villi growth, and did not cause pathology in the rodents' abdominal viscera, suggesting potential nutritional benefit as substitution for refined sugars in animal feed.

Phytochemistry, pharmacology and ethnomedicinal uses of Ficus thonningii (Blume Moraceae): a review

The common wild fig, Ficus thonningii, is extensively used in African ethnomedicine for treating a number of disease conditions which include diarrhoea, urinary tract infections, diabetes mellitus, gonorrhoea, respiratory infections, and mental illnesses. This review aims to present a logical analysis of the nutritional, phytochemical and pharmacological properties of F. thonningii in relation to its therapeutic applications. A bibliographic analysis of the uses, phytochemical constituents and phytophamacological properties of Ficus thonningii was carried out using published papers, medicinal plant databases and various ethnobotanical and ethnopharmacological books. Ficus thonningii contains various bioactive compounds which include alkaloids, terpenoids, flavonoids, tannins and active proteins, all of which contribute to its curative properties. In vitro and in vivo pharmacological studies revealed that F. thonningii possesses antimicrobial, antidiarrhoeal, antihelmintic, antioxidant, anti-inflammatory and analgesic properties. Acute and sub-chronic toxicity studies have shown that Ficus thonningii is non-toxic if administered orally in low doses. Scientific research has validated the ethnomedicinal claims that Ficus thonningii is useful in disease management. However, there is need to continue identifying, isolating and quantifying the active principles and possibly determine the mechanisms underlying its curative properties.

The effects of crude aqueous and alcohol extracts of Aloe vera on growth and abdominal viscera of suckling rats

The gastrointestinal tract of neonates is sensitive to dietary manipulations. When nursing mothers use Aloe vera, their babies are at risk of indirect exposure to Aloe vera via breast feeding or directly as health supplements. The effects of orally administered extracts of Aloe vera in unweaned rats were investigated. Six day old Sprague-Dawley rats were gavaged with aqueous or alcohol extracts of Aloe vera (low dose 50mg. kg⁻¹ or high dose 500mg. kg⁻¹) daily for eight days. All data were expressed as mean ± SD and analyzed by one way ANOVA. Pups receiving high doses of either extract had a significantly higher body mass gain than the group receiving lower dose (p < 0.05). Tibial length was significantly increased in the high dose aqueous extract group (15-26%). The differences in growth could not be attributed to circulating insulin-like growth factor-1 as the levels were not significantly different. The caecum was significantly enlarged in the rats that received the high doses of both extracts. Although, there was no significant difference in the non-fasting plasma concentration of glucose and triglycerides, the hepatic lipid and glycogen content were significantly higher (p < 0.001) for the high dose aqueous extract group. The plasma alanine transaminase was not affected by the treatments, however the high doses of the extracts significantly increased plasma alkaline phosphatase activity. Short term administration of Aloe vera extracts resulted in growth promotion, enhanced hepatic storage of metabolic substrates, increased ALP possibly in relation to bone growth and caused hypertrophy of the caecum of neonatal rats. These effects need to be explored further to enhance animal production and health.

Nutraceutical values of natural honey and its contribution to human health and wealth

The use of natural honey (NH) as a nutraceutical agent is associated with nutritional benefits and therapeutic promises. NH is widely accepted as food and medicine by all generations, traditions and civilizations, both ancient and modern. The nutritional profiles, including its use in infant and children feeding reported in different literatures as well as health indices and biomarkers observed by various researchers are illustrated in this manuscript. The review documents folk medicine, experimentation with animal models, and orthodox medical practices shown by clinical trials. This covers virtually all human organs and body systems extensively studied by different workers. The sources and adverse effects of NH contamination, as well as the preventive methods are identified. This could promote the availability of residue free honey and a wholesome natural product for domestic consumption and international market. This could also help to prevent health problems associated with NH poisoning. In addition, apicultural practices and the economic importance of honey are well documented. This report also includes information about a relatively unknown and uncommon South American stingless bee species. We concluded this review by identifying important roles for Ethno-entomologists, other Scientists and Apiculturists in the development of stingless bees to boost honey production, consumption and economic earnings.

Uterine torsion in a Sprague Dawley rat (Rattus norvegicus)

Uterine torsion is a twisting of the uterus or uterine horn perpendicular to its long axis. We report a case of uterine torsion in an adult breeding Sprague Dawley rat. The rat died a month after her last recorded delivery. Post mortem examination of the rat revealed 270 degrees torsion of the right uterine horn. The uterus contained a single foetus. The liver was pale and enlarged. The rest of the viscera appeared normal. Histopathological examination showed acute hepatic necrosis and pulmonary congestion with mild lymphocytic infiltrates peribronchially. The acute hepatic necrosis may have been associated with septicaemia due to compromised blood vessels following the uterine torsion. The presence of a single foetus could have resulted in foeto-maternal disproportion with resultant uterine torsion. Torsion of the uterus can be accompanied by haemostatic and metabolic complications, which could have caused the death of the rat. Although uterine torsion is a rare condition in rats, it should be considered as a potential complication of gestation in animal breeding units.

Hepatic capillariasis in a Cape ground squirrel (Xerus inaurus)

We report, for the first time, an incidental finding of Calodium hepaticum infestation in a sub-adult female Cape ground squirrel (Xerus inaurus). Post mortem examination of the squirrel revealed severe haemoperitoneum, splenomegaly and hepatomegaly with miliary white spots distributed diffusely throughout the hepatic parenchyma. Histologically the portal tracts in the liver showed granulomatous inflammation with fibrosis and numerous giant cells. Occasional adult worms were identified and there were multiple C. hepaticum eggs distributed diffusely throughout the portal tracts and the parenchyma. The spleen also contained C. hepaticum eggs. The genus Rattus is the primary host and reservoir of C. hepaticum, but C. hepaticum infections have been reported previously in other Sciuridae. Based on our findings, people should be cautious of the zoonotic potential of C. hepaticum, when they come into contact with the Cape ground squirrel.

Hyperzincaemia in a pet African giant rat (Cricetomys gambianus Waterhouse, 1840)

Presented is an African giant rat (Cricetomys gambianus) following zinc ingestion. The sick rat was lethargic, withdrawn, had soft, mucus-impregnated faeces and diahorrea, foot twitching and icterus. Comparative age, sex and body weight (b.wt.)-matched analyses were made with a healthy giant rat. Twelve-hourly Urine volume (UV), Haematocrit (Hct), urinary glucose, plasma zinc and Alkaline Phosphatase (ALP) were performed over an 8-week period. Full blood counts were performed and differential WBC counts and microscopic observations were made on blood smears obtained from both healthy and sick rats. Consecutive blood samples were drawn at the end of each week (Weeks <2-6 treatment; Weeks 7-8 post-treatment). Treatment involved oral vitamin B12 supplement at 4 microg/day and 2 ml diethylenetriaminepentaacetic acid (DTPA) intramuscular injections at 1 ml/450g b.wt./5 wks (Week 2 - 6). Day 1 showed neutropaenia, Heinz bodies on RBCs (reticulocytes and immature forms). Zinc (Day 1 - end Week 7), glucose (Day 1 - end Week 4), ALP (Day 1 -Week 4) and UV were elevated (Day 1 - end Week 6). Indications of moderate zinc toxicosis following ingestion and stress-associated glucosuria were concluded.

The effects of orally administered crude alcohol and aqueous extracts of African potato (Hypoxis hemerocallidea) corm on the morphometry of viscera of suckling rats

The litter from six Sprague-Dawley rats was used to study the short-term effects of African potato (AP) corm extracts in suckling rats. Ten days after birth, the pups in each litter were assigned to treatment groups and received alcohol (AL) or aqueous (AQ) extracts of AP (50 mg kg(-1) b.w. in 0.9% saline, 10 ml kg(-1) b.w., and a high dose 200 mg kg(-1) b.w. in 0.9% saline, 10 ml kg(-1) b.w.) via a stomach tube, for 5 consecutive days. A fifth group (control) received 0.9% saline (10 ml kg(-1) b.w.). Between gavage, the pups were kept with their dams. The pups were then killed and the viscera removed for gross and microscopic morphometric measurements. The low dose of AQ and AL extracts of AP significantly increased (P<0.01, ANOVA) the mean weight gain. The high dose of AQ significantly increased (P<0.05, ANOVA) the weight of the caeca whilst the low dose of the AL extract reduced pancreas weight compared to the control and low dose AQ groups. All other morphometric parameters of the viscera measured did not differ significantly between the groups. The small intestinal villi and crypts did not reveal any signs of pathology.

Effects of antisecretory factor-derived peptides on contractions in guinea pig colon

Two antisecretory factor (AF)-derived peptides have been studied in relation to effects on motility of guinea pig colon. Colon segments were isolated from adult guinea pigs and incubated in Tyrode Ringer. Motility was measured as the force and frequency of contractions upon addition of the derived peptides AF 1 (8 amino acids (aa)) and AF 3 (10 amino acids). At the lowest concentration (5 pM), peptide AF 1 induced a negative effect on the force of contraction in colon segments; an effect that was abolished by the cholinergic agonist carbachol. Peptide AF 3 induced a significant increase in the force of colon contractions at all concentrations (5-180 pM), with carbachol only reducing the effect of peptide AF 3 at a concentration of 15 pM. Both peptides increased contractile frequency, although the overall response was lower for peptide AF 3 than for peptide AF 1. It is concluded that antisecretory factor-derived peptides may play a role in regulating colon motility such that under pathophysiological conditions, they may serve to hasten the evacuation of noxious agents from the large intestine.

Gastrointestinal-tract models and techniques for use in safety pharmacology

The gastrointestinal tract (GI tract), which extracts nutrients, electrolytes, minerals, and water, is prone to injury as a result of oral drug administration. Clinical assessment of the GI tract is often limited to measurements of transit time and observations of vomiting or diarrhoea, despite the existence of methods and techniques capable of assessing specific changes in GI function at the membrane, cell, and whole animal levels. Membrane studies, record the uptake of solutes, and electrolyte transport, assessing the affects of compounds on transepithelial GI transport and flux. Such methods lend themselves to permeability, immunohistochemistry, morphology, and molecular biology techniques. Isolated cells from the GI tract or cultured cell lines provide knowledge of regulation and function at a cellular level, whilst motility patterns, taken in vivo or from biopsies, provide information at a more integrated level. In anesthetised animals, ligated segments of the intestine can be infused with test compounds, providing information about absorptive and secretory processes important for the treatment of diarrhoea. Computer simulations and modelling are used to predict the disposition of a chemical and its metabolite and can, to some extent, replace animal testing, thereby reducing development costs. Indeed, software programs can be used to simulate the dissolution, absorption, distribution, metabolism, and excretion (ADME) properties of potential drugs in the human GI tract. Finally, advances in the field of imaging, combined with endoscopy, have resulted in a wireless capsule, allowing the inspection of the GI tract anatomy and pathology without surgical intervention. It is concluded that the field of safety pharmacology could rapidly, cheaply, and routinely incorporate membrane, isolated tissue, and endoscopy techniques for GI tract testing of drugs.

Enteral crude red kidney bean (Phaseolus vulgaris) lectin--phytohemagglutinin--induces maturational changes in the enterocyte membrane proteins of suckling rats

This study aimed to investigate the effect of enterally administered crude red kidney bean (Phaseolus vulgaris) lectin, PHA, on the expression of brush-border membrane vesicle (BBMV) proteins, in particular Na(+)/H(+) exchangers (NHEs), in the small intestine of suckling rats. Gavage of PHA to 14-day-old rats for 3 days resulted in altered protein/glycoprotein patterns as analyzed by SDS-PAGE. Immunoblots demonstrated the appearance of two 71- and 27-kD protein bands indicative for NHE3--one of the NHE isoforms--and PHA, respectively. PHA treatment also resulted in an augmented uptake of (22)Na(+) by the BBMV indicating an increase in NHE activity. Overall, the data suggests that enteral PHA exposure may induce maturational changes in enterocyte membrane proteins in young rats. In view of these findings, an investigation into the addition of PHA to infant formulas and weaning diets is warranted.

Does the ostrich (Struthio camelus) coprodeum have the electrophysiological properties and microstructure of other birds?

The ostrich is unique among birds in having complete separation of urine and faeces. The coprodeal epithelium is thus during dehydration exposed to a fluid 500 mOsm hyperosmotic to plasma. We have investigated whether the coprodeum is adapted like a mammalian bladder. The coprodeal epithelium was studied by electrophysiology in the Ussing chamber, and the anatomy by light microscopy and scanning electron microscopy.

ELECTROPHYSIOLOGY

The short-circuit current (SCC) and open circuit electrical potential difference were recorded. The change induced by 0.1 mmol mucosal amiloride was recorded. An average basal SCC of 162+/-29 microA/cm(2) was observed, and a resistance of 297+/-34 Omega cm(2) calculated. These values are as observed in other avian coprodea. The resistance is much lower than in mammalian bladders (10000 Omega cm(2)). The amiloride-sensitive SCC, equal to net sodium absorption, was approximately 5 micromol/cm(2)h as observed in other avian species.

ANATOMY

The mucosal membrane is composed of broad irregular folds with very short intestinal glands containing an unusually high proportion of goblet cells.

CONCLUSION

The ostrich coprodeum is not adapted like a mammalian bladder. The abundance of goblet cells results in a copious secretion of mucus that establishes a thick unstirred layer giving effective osmotic protection.

Effects of dietary substitution with raw and heat-treated cowpea (Vigna unguiculata) on intestinal transport and pancreatic enzymes in the pig

Tropical grain legumes represent potentially important feed for farm animals. However, diarrhoea and poor growth performance have been reported, due to the various anti-nutritional factors they contain. This study addressed in particular whether dietary cowpea impaired the growth of pigs, whether the small intestinal Na+/D-glucose coabsorptive transport capacity was decreased, whether the Cl- secretory capacity was increased, and, finally, whether these parameters were affected by heat treatment of cowpea. Pigs, 4 weeks old, were fed for 3 weeks with one of three diets: (i) standard soy, (ii) 75% of soy substituted with raw cowpea, or (iii) 75% of soy substituted with heat-treated cowpea. The absorptive and secretory capacities of the jejunum and ileum were measured with the Ussing chamber technique. Weight gain, feed intake, pancreatic protein and enzyme concentrations and levels of the blood hormones glucagon and cholecystokinin were also measured. The Na+ transport capacity was measured as the increase in short-circuit current (Isc) when D-glucose was added to the luminal side in the Ussing chambers. Isc was significantly higher in the jejunum from raw cowpea-fed pigs than in the jejunum from standard soy-fed pigs, with no difference between the two cowpea-fed groups. The phosphodiesterase inhibitor theophylline was subsequently added bilaterally, and the increase in Isc indicated the cAMP-depedent Cl- secretory capacity. In the jejunum this was significantly higher in raw and heat-treated cowpea-fed pigs than in standard soy-fed pigs. In contrast, there were no differences in the ileal transport capacities. There were no differences in the pancreatic protein and trypsin concentrations or the blood hormones, but the raw cowpea-fed pigs had significantly lower pancreatic amylase than standard soy-fed pigs. Weight gain and feed intake were lowest in the cowpea-fed groups, with no significant difference between the two groups. In conclusion, the hypothesis of impaired small intestinal absorption of D-glucose and Na+ as causing malabsorption, and therefore impaired growth, during cowpea substitution in the feed may be firmly rejected. The increased Cl- secretory capacity, although moderate, may contribute to the higher incidence of post-weaning diarrhoea in cowpea-fed pigs, as observed in other studies. Additionally, the decreased food intake, feed conversion and weight gain were unaffected by heat treatment, further suggesting involvement of heat-stable anti-nutritional factors.

Effect of age on vasoactive intestinal polypeptide-induced short-circuit current in porcine jejunum

Vasoactive intestinal polypeptide is a transmitter at the neuroepithelial junction of the small intestine in cholera toxin-induced secretion. We investigated whether the secretory effect in vitro of vasoactive intestinal polypeptide in porcine jejunum was changed with age. Stripped tissue preparations from three age groups, neonatal (7-11 days), young (6-8 weeks) and adult (13-15 weeks) pigs, were mounted in Ussing chambers and short-circuited. Vasoactive intestinal polypeptide produced concentration dependent increases in short-circuit current in all three age groups with EC50 values (in nM) of 14.5 +/- 1.9, 16.2 +/- 2.0 and 147 +/- 0 in neonatal, young and adult pigs, respectively. The peak increases in short-circuit current in adult pigs were significantly decreased compared with the other two age groups. To evaluate the secretory capacity, theophylline was added to tissue preparations in which baseline short-circuit current again was established. Theophylline caused a significantly lesser increase in short-circuit current in adult pigs (25.4 +/- 2.0 microA.cm-2) than neonatal (57.1 +/- 3.6 microA.cm-2) and young pigs (63.1 +/- 2.9 microA.cm-2). In conclusion, vasoactive intestinal polypeptide showed a marked decrease in the secretory response with age in porcine jejunum, at least partly caused by a reduced secretory capacity of the enterocytes.