Effect of elevated dietary amino acid levels in high canola meal diets on productive traits and cecal microbiota population of broiler chickens in a pair-feeding study
A pair-feeding study was conducted to determine if reduced feed intake (FI) in broiler chickens fed high canola meal (CM) diets per se accounts for reduced growth performance and whether this lower growth rate can be mitigated by increasing dietary amino acid (AA) levels. Five experimental wheat-based diets were formulated as follows: soybean meal (SBM) diet, high CM diet with normal AA concentration, and high CM diets with 3, 6, or 9% additional AA concentration (Lys, Met+Cys, Thr, Ile, Arg, and Val). Another group of birds was pairfed with SBM diet to the consumption levels of birds fed CM diet with normal AA. There were 6 replicates of 17 male 10-day-old Ross 308 chicks per treatment over grower and finisher periods. Birds fed the CM diets had reduced FI and BWG, but improved FCR (P < 0.01) compared to SBM ad libitum fed birds. The SBM pair-fed birds gained the same weight and exhibited similar FCR compared to CM fed birds. Additional 9% AA improved FCR (P < 0.01) compared to SBM and CM diets with normal AA. No significant differences were observed in ileal digestibility of DM, energy, crude protein, and AA between CM with normal AA and SBM diets. The additional 6 and 9% AA in CM diets increased digestibility of crude protein and some AA (P < 0.05). SBM ad libitum and CM + 6 and 9% AA fed birds had the highest and lowest relative weight of abdominal fat, respectively (P < 0.05). Addition of 6 and 9% AA in CM diets increased relative carcass and breast yields (P < 0.01). Serum triglyceride level was higher in SBM ad libitum fed birds (P < 0.05). The composition of microbiota in the ceca was not affected by treatments. This study showed that reduced growth of birds fed high CM diets is primarily mediated through reduced FI. This growth depression could partially be ameliorated by increasing dietary AA levels.
Nutritional value of canola meal for broiler chickens as affected by processing conditions, microbial enzymes and essential amino acids
Four experiments were conducted to assess the effects of processing conditions on nutritional value of expeller-extracted canola meal (ECM) and the replacement value of expeller and cold-pressed canola meals in broiler chicken diets. The first two experiments evaluated and characterized the effect of processing conditions such as conditioning temperature (90, 95 or 100 °C) and screw torque (high or low) during oil extraction process on apparent metabolizable energy (AME), apparent and standardised ileal digestibility of amino acids of ECM for broiler chickens. The values obtained in these two experiments were used to formulate diets with high inclusion of ECM to investigate the effect of a microbial multi-carbohydrase obtained by fermentation from 'Aspergillus aculeatus' (Ronozyme® VP), and a microbial mono-component protease (Ronozyme® ProAct), in diets on productive traits, nutrient digestibility and partitioning of energy in broiler chickens. The fourth experiment was designed to determine if reduced feed intake of birds fed CM-based diets, per se accounts for growth depression and if this retarded growth rate can be attenuated by increasing dietary digestible amino acid levels of the diet.
Impact of processing conditions and chemical composition on energy utilisation of expeller-extracted canola meal for broiler chickens
Low metabolizable energy content is regarded as one of the factors restricting high inclusion level of canola meal (CM) in broiler diets. It is known that expeller-extracted CM has higher energy content than solvent-extracted CM because the former contains higher residual oil (Woyengo et al., 2010). However, the impact of other chemical constituents is usually overlooked. The present study was designed to investigate the effect of processing conditions and chemical composition on AME and AMEn of six expeller-extracted canola meal samples (ECM) subjected to 90, 95 or 100° C and high or low screw force during oil extraction. The ECM samples were incorporated into a corn-soybean meal reference diet at 300 g/kg by replacing the energy yielding ingredients. A total of 210 day-old male broiler chicks (Ross 308) were fed a common starter and grower diet until 18 d of age, and then were assigned to each of seven experimental diets replicated six times with five chicks per cage. After a 5-d diet acclimation period from 18 to 22 d of age, a 72-h excreta collection period from 22 to 25 d was conducted. The difference method was used to determine AME which was corrected to zero N balance to obtain AMEn.