Nadia Yacoubi

Expeller soybean (ESB) is a widely used protein source in broiler diets due to its high amino acid digestibility. However, improper heat processing of ESB can negatively affect nutrient digestion, absorption, and metabolism leading to decreased growth performance. The study aimed to investigate the impact of varying processing temperatures on growth performance, amino acid digestibility (AID), and intestinal integrity using 3 different commercial batches of ESB processed at distinct… Show more

Expeller soybean (ESB) is a widely used protein source in broiler diets due to its high amino acid digestibility. However, improper heat processing of ESB can negatively affect nutrient digestion, absorption, and metabolism leading to decreased growth performance. The study aimed to investigate the impact of varying processing temperatures on growth performance, amino acid digestibility (AID), and intestinal integrity using 3 different commercial batches of ESB processed at distinct temperatures. These temperatures were 182°C (normal-control), 199°C (overcooked), and 154°C (undercooked). 1,860 off-sex male Cobb 500 broilers were allocated randomly to these treatments, with 10 replicate floor pens (62 birds/pen) from 1 to 35 d of age. Birds consuming the overcooked ESB exhibited significantly lower body weight gain (BWG) and feed intake (FI) on d 14, 28, and 35. They also showed higher feed conversion ratio (FCR) and smaller relative right pectoralis major (RPM) weights at d 35. Meanwhile, birds fed undercooked ESB demonstrated reduced BWG at d 14. Serum fluorescein isothiocyanate-dextran (FITC-d; 4 kD) concentrations on d 16 were notably elevated in birds fed overcooked ESB, indicating increased gut permeability. Overcooked ESB reduced the AID coefficients of several amino acids on d 14 and 28, with Lys experiencing the highest reduction (8%). Undercooked ESB, however, mainly affected the AID of Val, and Phe at d 28. In conclusion, overcooked ESB decreased amino acid digestibility, impaired gut barrier function, and led to diminished growth performance. Conversely, undercooked ESB primarily affected the digestibility of Val and Phe and resulted in reduced BWG at d 14. These findings underscore the critical role of proper heat processing in preserving the nutritional quality of ESB in broiler diets, influencing optimal growth performance, and maintaining intestinal health. Show less

Highlights
The regression method allowed to determine metabolizable energy of insect meal and tilapia byproduct meal for broilers.
The metabolizable energy of Tenebrio molitor larvae meal for broilers was 21.93 MJ/kg.
The metabolizable energy of tilapia byproduct meal for broilers was 14.29 MJ/kg.

This study investigated the effect of Rovabio® Advance (Enz), containing high levels of endo-xylanase (Xyl) and arabinofuranosidase (Abf) activities, on energy and ileal amino acid (AA) digestibility of a complete wheat/soybean-based diet in broilers. The commercial control diet was compared with a 3% nutrient-diluted version using silica as inert diluent. Digestibility of dry matter, AA, and gross energy were determined by analysis of feed, excreta, and digesta. Ross PM3 broiler chicks were… Show more

This study investigated the effect of Rovabio® Advance (Enz), containing high levels of endo-xylanase (Xyl) and arabinofuranosidase (Abf) activities, on energy and ileal amino acid (AA) digestibility of a complete wheat/soybean-based diet in broilers. The commercial control diet was compared with a 3% nutrient-diluted version using silica as inert diluent. Digestibility of dry matter, AA, and gross energy were determined by analysis of feed, excreta, and digesta. Ross PM3 broiler chicks were studied during the grower period, and diet dilution did not cause feed intake to increase. Fecal energy digestibility was similar (approximating 73%) for diets without Enz (P = 0.99). However, apparent metabolizable energy (AME) content was significantly lower in the diluted vs. control diet. Enz improved energy utilization (P < 0.001), leading to an increase of AME content of the diluted and standard diets. AME content of the diluted diet with Enz was similar to that of the standard diet without Enz (P = 0.98), demonstrating the ability of Enz to fully compensate the 3% nutrient dilution. At ileal level, AA digestibility was around 75% across all treatments. The addition of Enz increased AA digestibility by an average of 4.4% (P < 0.001). Show less

Carbohydrate-degrading multi-enzyme preparations (MEP) are used to improve broiler performances. Their mode of action is complex and not fully understood. In this study, we compared the effect of water-soluble fractions isolated at the pilot scale from wheat grain incubated with (WE) and without (WC) MEP. The fractions were incorporated in a wheat-based diet (0.1% w/w) to feed Ross PM3 broilers and compared with a non-supplemented control group (NC). The MEP treatment increased the amount of… Show more

Carbohydrate-degrading multi-enzyme preparations (MEP) are used to improve broiler performances. Their mode of action is complex and not fully understood. In this study, we compared the effect of water-soluble fractions isolated at the pilot scale from wheat grain incubated with (WE) and without (WC) MEP. The fractions were incorporated in a wheat-based diet (0.1% w/w) to feed Ross PM3 broilers and compared with a non-supplemented control group (NC). The MEP treatment increased the amount of water-soluble arabinoxylans (AX) and reduced their molecular weight while retaining their polymer behavior. The WE fraction significantly (P < 0.05) increased FI by 13.8% and BWG by 14.7% during the first wk post hatch when compared to NC. No significant effect on FCR was recorded during the trial. The WE increased the abundance of Enterococcus durans and Candidatus arthromitus in the ileum and of bacteria within the Lachnospiraceae and Ruminococcaceae families, containing abundant butyrate-producing bacteria, in the ceca. It also increased the concentration of SCFA in the ceca, decreased the T-lymphocyte infiltration in the intestinal mucosa, and increased the glucagon-like-peptide-2 (GLP-2)-producing L-cell density in the ileal epithelium compared with WC and NC. No significant effects were observed on villi length. These results showed that AX present in the WE fraction altered the microbiota composition towards butyrate producers in the ceca. Butyrate may be responsible for the reduction of inflammation, as suggested by the decrease in T-lymphocyte infiltration, which may explain the higher feed intake leading to improved animal growth. Show less

Carbohydrate-degrading enzyme preparations (MEP) are used to improve broilers performance. Their mode of action is complex and not fully understood. In this PhD work, we first studied the effects of MEP on wheat grain by characterizing the different water-soluble fractions produced with and without MEP. These fractions were incorporated in a wheat-based diet (0.1% w/w) to feed broilers during the first 2 weeks post-hatch to investigate the production of short-chain fatty acids (SCFA) and the… Show more

Carbohydrate-degrading enzyme preparations (MEP) are used to improve broilers performance. Their mode of action is complex and not fully understood. In this PhD work, we first studied the effects of MEP on wheat grain by characterizing the different water-soluble fractions produced with and without MEP. These fractions were incorporated in a wheat-based diet (0.1% w/w) to feed broilers during the first 2 weeks post-hatch to investigate the production of short-chain fatty acids (SCFA) and the diversity of intestinal microbiota, and finally the animal performance and intestinal health. Enzymatic treatment increased the amount of water-soluble arabinoxylans (AX) and reduced their molecular weight. Nevertheless, degradation products were short chain AX polymers (SC-AX) and not oligosaccharides. SC-AX produced by enzymatic treatment significantly increased body weight gain and the abundance of bacteria within the Lachnospiraceae and Ruminococcaceae families in the ceca. Accordingly, the concentration of SCFA, mainly butyrate and acetate, increased in the ceca. In addition, the T-lymphocyte infiltration decreased in the cecal and ileal mucosa while the L-cell density increased in the ileal epithelium. These results indicate that SC-AX favored the growth of butyrate producers and decreased inflammation in the intestinal tract. This effect was likely due to butyrate known to have anti-inflammatory effects and to stimulate enteroendocrine L-cells that produce hormones with beneficial effect on small intestine function, hereby improving animal performance. Show less

The use of exogenous cell wall degrading enzymes to improve the nutritional values of cereal grains has increased during the last decades. In this study, products from enzymatic hydrolysis of wheat grain were isolated and their ability to induce short-chain fatty acids was investigated using in vitro fermentation with cecal microbiota. Water-soluble fractions were obtained following incubation without and with a multicomponent enzyme preparation (MEP) (2 mL/kg) containing essentially… Show more

The use of exogenous cell wall degrading enzymes to improve the nutritional values of cereal grains has increased during the last decades. In this study, products from enzymatic hydrolysis of wheat grain were isolated and their ability to induce short-chain fatty acids was investigated using in vitro fermentation with cecal microbiota. Water-soluble fractions were obtained following incubation without and with a multicomponent enzyme preparation (MEP) (2 mL/kg) containing essentially endoxylanase and endoglucanase activities. These were further fractionated by size exclusion chromatography into high molecular weight (HMw) and low molecular weight (LMw) sub-fractions. The MEP treatment increased the content in water-soluble arabinoxylan (AX) and decreased the degree of polymerization (DP) of the xylan-backbone. In vitro fermentation assays using broiler cecal content as inoculum demonstrated that low substituted AX with reduced molecular weight isolated after MEP treatment yielded higher concentrations of acetate and butyrate. This result indicates that cecal fermentation of enzymatic degradation products into short-chain fatty acids, particularly butyrate, is one of the important mechanisms of MEP action on wheat-based diets that can contribute to the improvement of intestinal health and animal performance. Show less