Impact of Feeding Fermented Palm Kernel Cake and High Dietary Fat on Nutrient Digestibility, Enzyme Activity, Intestinal Morphology and Intestinal Nutrient Transporters mRNA Expression in Broiler Chickens under Hot and Humid Conditions

The study aimed at determining the ileal nutrient digestibility, digestive enzyme activity, intestinal morphology, and nutrient transporters mRNA expressions in broiler chickens fed with fermented PKC (LPKC) based diets with different levels of fat supplementation under hot and humid conditions. From day 22 to 35, broiler chickens were randomly fed with either (1) 20% LPKC-based diet with 5% palm oil, (2) 20% LPKC based diet with 9.5% palm oil, (3) 20% PKC-based diet with 5% palm oil or (4) 20% PKC-based diet with 9.5% palm oil. Feeding LPKC and PKC diets at the finisher phase have not affected the nutrient’s digestibility, but a higher level of oil supplementation does. This was seconded by changes in the digestive enzyme activity, villus height, and mRNA expression of nutrient transporters in the higher level of oil-supplemented diets fed chickens. In conclusion, the inclusion of oil at 9.5% in a 20% LPKC/PKC-based diet is necessary to ensure better nutrient digestibility in chickens via improved digestive function, especially in hot and humid tropical regions.

Upgrading the Nutritional Value of PKC Using a Bacillus subtilis Derived Monocomponent β-Mannanase

Palm kernel cake (PKC) is an abundant side stream that can only be added to non-ruminant feed in small concentrations due to its content of antinutritional factors, mainly galactomannan, which cannot be digested by non-ruminants. β-mannanases can be added to partially hydrolyze galactomannan to form mannose oligosaccharides, which are known to be prebiotic. We here investigate the action of a β-mannanase from B. subtilis on PKC by colorimetry, NMR and fluorescence microscopy. The amount of mannan oligosaccharides in solution was significantly increased by the β-mannanase and their degree of polymerization (DP) was significantly reduced. There was a dose-response behavior in that larger β-mannanase concentrations increased the amount of soluble mannose oligosaccharides while reducing their average DP. Using confocal immunofluorescence microscopy, solubilization of galactomannan in PKC was clearly visualized. Images show a clear disruption of the cellulose and galactomannan structures of the PKC cell walls. We thus show in this study that using commercial dosages of β-mannanase on PKC can lead to formation of prebiotic compounds. Thus, this study suggests that utilization of PKC in poultry feed formulation might be increased by addition of a β-mannanase and would improve the return on investment.

Extrusion enhances apparent metabolizable energy, ileal protein and amino acid digestibility of palm kernel cake in broilers

Objective

This study consisted of two stages; the first was to determine the effect of extrusion and sieving treatments on the chemical properties of palm kernel cake (PKC), and accordingly, a follow-up experiment (second stage) was conducted to determine and compare the apparent metabolizable energy (AME), and protein and amino acid digestibility of extruded and sieved PKC.

Methods

Two physical treatments, namely extrusion (using temperature profiles of 90°C/100°C/100°C, 90°C/100°C/110°C, and 90°C/100°C/120°C) and sieving (to 8 particles sizes ranging from >8.00 to 0.15 mm) were carried out to determine their effects on chemical properties, primarily crude protein (CP) and fiber contents of PKC. Based on the results from the above study, PKC that extruded with temperature profile 90/100/110°C and of sieved size between 1.5 to 0.15 mm (which made up of near 60% of total samples) were used to determine treatments effect on AME and CP and amino acid digestibility. The second stage experiment was conducted using 64 male Cobb 500 chickens randomly assigned to 16 cages (4 cages [or replicates] per treatment) to the following four dietary groups: i) basal (control) diet, ii) basal diet containing 20% untreated PKC, iii) basal diet containing 20% extruded PKC (EPKC), and iv) basal diet containing 20% sieved PKC (SPKC).

Results

Extrusion and sieving had no effect on CP and ash contents of PKC, however, both treatments reduced (p<0.05) crude fiber by 21% and 19%, respectively. Overall, extrusion and sieving reduced content of most of the amino acids except for aspartate, glutamate, alanine and lysine which increased, while serine, cysteine and tryptophan remained unchanged. Extrusion resulted in 6% increase (p<0.05) in AME and enhanced CP digestibility (p<0.05) by 32%, as compared to the untreated PKC while sieving had no effect on AME but improved CP digestibility by 39% which was not significantly different from that by extrusion.

Conclusion

Extrusion is more effective than sieving and serves as a practical method to enhance AME and digestibility of CP and several amino acids in broiler chickens.

Effect of dietary raw and fermented sour cherry kernel (Prunus cerasus L.) on growth performance, carcass traits, and meat quality in broiler chickens

Sour cherry kernels are waste products of the fruit juice industry. Solid-state fermentation has great potential for recycling the agro-industrial residues. In the present study, the effect of raw sour cherry kernel (RC) and fermented sour cherry kernel (FC) by Aspergillus niger on growth performance, carcass traits and meat quality in broiler chickens was investigated. A total of 343 one-day-old male broilers (Ross 308) were randomly allocated to 7 treatments with 7 replicates for each treatment and 7 birds in each replicate. The chicks were fed on a basal diet (control) and basal diet supplemented with RC or FC at the 1, 2, and 4% level. Dietary RC improved (P < 0.001) the feed conversion ratio (FCR) at the 1% inclusion level although chicks fed 2 and 4% RC had lower (P < 0.01) body weight (BW), body weight gain (BWG), and feed intake (FI) from day 1 to 42, compared with that of the birds in the control group. Dietary FC with 1% inclusion level increased (P ≤ 0.05) BWG from day 22 to 42 and also enhanced (P < 0.001) the FCR from day 1 to 42. However, 4% dietary FC had an adverse effect (P < 0.01) on BW, BWG, FI, and the FCR, compared with the control group. The bursa of Fabricius weight was raised (P < 0.01) as the supplemental FC level increased. Dietary RC and FC elevated gut weight (P < 0.01) and length (P ≤ 0.05). Broilers fed on 2% FC had a higher (P ≤ 0.05) ash level and a lower (P ≤ 0.05) b* value in thigh meat, compared with the 2% RC group. The results indicate that FC can be used in broiler nutrition up to 2% level although RC can be added to broiler diets up to 1% level without a detrimental effect on growth performance. Dietary inclusion of 1% RC or FC can be recommended due to the positive effects on broiler chickens.

Effect of dietary raw and fermented sour cherry kernel (Prunus cerasus L.) on digestibility, intestinal morphology and caecal microflora in broiler chickens

This study was conducted to investigate the effect of dietary raw sour cherry kernel (RC) or fermented sour cherry kernel (FC) on apparent digestibility, ileal morphology, and caecal microflora in broiler chickens. Raw sour cherry kernel was fermented by Aspergillus niger for 7 D. A total of 343 one-day-old Ross 308 male chicks were assigned to 7 dietary treatments consisting of 7 replicates of 7 broilers each. All birds were fed with a commercial diet or diets supplemented with 1%, 2%, or 4% RC or FC. The experimental period was 42 D. Apparent dry matter (DM), nitrogen and ash digestibilities were diminished (P < 0.05) by dietary RC inclusion, although dietary FC did not negatively affect (P > 0.05) nutrient digestibility. Dietary 1% FC increased (P < 0.01) the villus height to crypt depth ratio (VH:CD) compared with the other treatment groups, although RC4 reduced the villus height (VH, P < 0.001) and VH:CD (P < 0.01), compared with the control group. Dietary treatments had no effect (P > 0.05) on the crypt depth (CD). Birds fed 1% FC had the highest (P < 0.05) caecal Lactobacillus spp. counts among the treatment groups. Enterococcus spp. and Escherichia coli counts in cecum were not affected (P > 0.05) by dietary treatments. The results showed that the dietary inclusion of 1% FC improved ileal morphology and caecal microflora without any adverse effect on the apparent digestibility. These results indicate that FC has the potential to be a feed additive which improves intestinal health for broiler diets.

Enzymatic hydrolysis drastically reduces fibre content of palm-kernel expeller, but without enhancing performance in broiler chickens

The effectiveness of enzymatic hydrolysis of palm-kernel expeller (PKE) is dependent on various factors that influence the stability and functionality of the enzymes. In the present study, parameters influencing the enzymatic treatment of PKE were optimised employing response surface methodology. In addition, the effectiveness of enzymatic hydrolysed PKE in increasing inclusion rates in broiler diets was evaluated. Results showed that temperature, enzyme concentration and duration of hydrolysis had significant (P &lt; 0.01) effects on the enzymatic hydrolysis of PKE. Using the crude enzyme produced by Aspergillus terreus K1 isolated in our laboratory, maximum reduction of crude fibre (40%) was achieved by fermenting the PKE at 60% initial moisture with 9.0 U/g PKE mannanase at 51°C for 18 h, with the production of 9.9% (w/w) of monosaccharides and oligosaccharides. Results of the growth-performance study indicated that inclusion rate of PKE with or without enzyme treatment in broiler diet is 5% for starter period and 20% for the finisher diet, without any detrimental effect on animal performance. Although the inclusion rate of enzyme-treated PKE can be increased to 30% without affecting average daily gain, feed conversion ratio of the birds will be compromised.