ABSTRACT

    Sausages have been a popular food made from minced meat for many years. However, recent studies have linked their consumption to non-communicable diseases (NCDs) such diabetes, gout, cardiovascular diseases (CVDs). Dietary habits have been reported to impact the gut microbiota composition and therefore affect firmicutes and Bacteroidetes which make up the majority of intestinal bacteria. There is a growing need to shift our diets away from meat-based sausages to alternative options which may impact the gut microflora. The effect of the consumption of newly developed forms of sausages and their effect on the gut microbiota, biochemical parameters and health in general. This research was to investigate how plant-based sausage (soybean curd) and animal-based sausage (fish) may affect the biochemical parameters and the gut microbial flora. This research was conducted in two phases. In Phase I: Sausages were produced from plant-based and animal-based sausage using standard recipes and seasonings.

Lizard fish sausage (FS) and tofu sausages (TS) were therefore produced after seasoning and manually stuffing into synthetic casings. After cooking by boiling (6hrs for tofu sausage and 20mins for fish sausage). Proximate analysis (protein, fat, fiber, carbohydrate, energy, vitamin A, moisture, dry matter and ash content) and phytochemical analysis (total phenolic content, tannins, flavonoids and saponins) of the resulting sausage using a commercial meat sausage (CMS) as a control. Phase II: To study the effect of the consumption of these three sausage types (CMS, TS and FS) on biochemical parameters, gut microbiota and health, an animal study was carried out. Twenty-four male albino rats were divided into four groups and fed different diets for 28 days. The rats’ body weight, food intake, and water intake were measured daily.

Group I was the control group and received a standard rat feed (ND). Group II was fed a diet containing 15% commercial meat sausages (CMSD), Group III received a diet with 15% tofu sausages (TSD), and Group IV was given a diet with 15% fish sausages (FSD). On the 27day the rats were fasted overnight and at the end of the experiment on day 28, the animals were sacrificed and blood collected for plasma and serum preparation (EDTA and dry tubes respectively) for full blood count on plasma and serum. Organs (liver, kidney, heart, and brain) were collected and homogenates were prepared for oxidative stress (MDA, GSH, SOD, NO and catalase) and albumin studies together with that of serum. Lipid profile (LDL, HDL, TG and TC) level and serum enzymes (AST, ALT, urea and creatinine) activities were assessed using commercial kits according to the manufacturer’s instructions.

Animal Fecal samples were also collected from the large intestines and cultured to identify and characterize specific types of bacteria. Nutritional analysis of the different sausage types showed that TS was high in fiber (10.66±0.13%), dry matter (52.1±0.14%), fat (49.43±0.56%), ash (6.41±1.88%), TPC (234.26±2.06mg GAE/g), tannins (4.0±0.80mg/g)), flavonoids (60.85±2.61 mg QC/g) and saponins (60.85±2.61 mg/g) and had low levels of carbohydrates (3.28±0.02%), energy (535.87±0.21Kcal/100g), and vitamin A (4.0±0.80 mg/100g) when compared to the other sausage types. FS results indicated high levels of proteins (69.78±0.79%) and moisture (68.09±0.13%) with low levels of other nutritional parameters when compared to the CMSD group.

The in vivo study showed that animals fed with CMSD had an adverse effect on hematological parameters, lipid profile results showed high levels of LDL (1.21±0.14mmol/L) and TC (2.19±0.14 mmol/L) at p<0.05 and low levels of HDL (0.42±0.01mmol/L) when compared to the TS and FS, serum activity of AST, ALT, urea and creatinine showed toxicity in the group fed with the CMSD as the had the highest levels of these enzymes (89.42±1.06U/L, 27.35±5.04U/L, 31.67±0.47umol/L and 2426.47±103.99mmol/L respectively)when compared to the TS(61.54±1.24U/L,  9.60±1.26U/L, 15.33±1.72nmol/L and  808.82±103.99mmol/L) followed by the FSD. Also TS in serum had high cocentrations of GSH (123.68±1.39Mmol/mg), SOD (0.09±0.01) and catalase (1.34±0.03 Mmol/H2O2/min.mg) with reduced concentrations of MDA (0.19±0.08uM/g) and NO (0.04±0.01mM/mg). The gut microbiota composition indicated high levels of bacteroidetes in the group fed with the TSD (5.0 x10^6 CFU/ml) and Lactobacillus (6.8 x10^6 CFU/ml) and had low levels of E. coli (3.9 x10^6 CFU/ml) and bifidobacteria (3.6 x10^6 CFU/ml) and when compared to the other groups. Tofu sausages and fish sausages should be consumed more as results have shown to have reduced risk of NCDs in rats fed with TSD and FSD when compared rats fed with commercial meat sausages had a higher risk of NCDs, including diabetes, cardiovascular diseases, and certain types of cancers.

Key words; Sausage, NCDs, biochemical parameters, Gut microbiota, Sausage, Firmicutes and bacteroidetes.