M.R. Abdollahi

Nutrient analysis, metabolizable energy, and digestible amino acids of soybean meals of different origins for broilers

Nutrient composition, ileal amino acid (AA) digestibility, and AME of 55 soybean meal (SBM) samples from the United States (US; n = 16), Argentina (ARG; n = 16), Brazil (BRA; n = 10), and India (IND; n = 13), collected from commercial mills in Southeast Asia, were compared using laboratory analyses and animal studies. There were significant (P < 0.05 to 0.001) differences due to origin in CP, fat, ash, fiber, and nonstarch polysaccharide (NSP) contents of SBM. The average CP content of US, ARG, BRA, and IND samples was determined to be 47.3, 46.9, 48.2, and 46.4% (as-fed basis), respectively. Compared with SBM from other origins, crude fiber and NSP contents were lower (P < 0.05) and sucrose content was higher (P < 0.05) in the US samples. The IND samples had the highest (P < 0.05) contents of fiber, ash, and NSP, and lowest (P < 0.05) contents of fat and sucrose. Differences (P < 0.0001) were observed among origins for in vitro protein quality measures (urease index, KOH protein solubility, and trypsin inhibitor activity). Significant (P < 0.001) effects due to origin were observed for all minerals. Soybean meal from the US and IND had higher (P < 0.05) calcium contents (0.45%) compared with those from ARG and BRA (0.28-0.31%). Phosphorus and potassium contents were lowest (P < 0.05) in SBM from IND, and no differences (P > 0.05) were observed in SBM from other origins. Iron content was markedly high (928 mg/kg) in SBM from IND compared with those from other origins (103-134 mg/kg). Major origin-related differences (P < 0.0001) were observed in the AME of SBM. The average AME content of US, ARG, BRA, and IND samples was 2,375, 2,227, 2,317, and 2,000 kcal/kg (as-fed basis), respectively. Total AA contents of US, ARG, BRA, and IND samples were similar (P > 0.05) for 9 of the 17 amino acids. Major differences (P < 0.05 to P < 0.001) due to origin were determined for the digestibility of all AA. The IND samples had the lowest (P < 0.05) digestibility and no differences (P > 0.05) between samples from other 3 origins. However, the digestible CP content of US SBM was higher (P < 0.05) than those of ARG and IND, but similar (P > 0.05) to that from BRA. The digestible CP contents of SBM from the US, ARG, BRA, and IND were 40.0, 38.6, 39.8, and 36.7%, respectively. Digestible contents of indispensable AA, in general, followed the same trend as that of digestible CP. In conclusion, the present evaluation showed that major differences in nutritive value do exist between SBM from different origins in terms of nutrient contents, AME, and digestible AA. Overall, SBM originating from the US had better nutritive value compared with those from ARG and IND, on the basis of AME and contents of digestible CP and digestible AA.

Influence of conditioning temperature on the performance, nutrient utilisation and digestive tract development of broilers fed on maize- and wheat-based diets

1. The influence of conditioning temperature on the performance, nutrient utilisation and digestive tract development of broilers fed on maize- and wheat-based diets was examined up to 21 d of age. The experimental design was a 2 × 3 factorial arrangement of treatments evaluating two grain types (maize and wheat) and three conditioning temperatures (60°C, 75°C and 90°C). Broiler starter diets, each based on one grain (maize or wheat), were formulated and pelleted at the three temperatures. 2. Increasing conditioning temperature decreased the body-weight gain and feed intake in wheat-based diets, but birds fed on maize-based diets conditioned at 60°C and 90°C had higher body-weight gain and feed intake than those fed on the diet conditioned at 75°C. Increasing conditioning temperature increased feed per body-weight gain in both grain-type diets but improved pellet durability index (PDI) only in wheat-based diets; PDI was unaffected in maize-based diets. 3. In wheat-based diets, increasing conditioning temperature decreased the ileal digestibility of nitrogen and starch. Ileal nitrogen digestibility of maize-based diets conditioned at 60°C and 90°C was higher than at 75°C. Starch digestibility was unaffected by conditioning temperature in maize-based diets. No effect of conditioning temperature was found for apparent metabolisable energy (AME). Increasing conditioning temperature decreased digestible protein and AME intakes in wheat-based diets but, in maize-based diets, birds fed on the diet conditioned at 75°C had lower digestible protein and AME intakes compared to those fed on diets conditioned at 60°C and 90°C. 4. Small intestine was longer in birds fed on diets conditioned at 75°C and 90°C compared with those fed on diets conditioned at 60°C. 5. Overall, the data suggest that while the effects of conditioning temperature on body-weight gain and feed intake of broilers to 21 d of age differed depending on the grain type, feed per body-weight gain was adversely affected by higher conditioning temperatures.

The effect of manipulation of pellet size (diameter and length) on pellet quality and performance, apparent metabolisable energy and ileal nutrient digestibility in broilers fed maize-based diets

A 2 by 2 factorial arrangement of treatments was used to evaluate the effect of pellet diameter (3 and 4.76 mm) and pellet length (3 and 6 mm) on pellet quality and performance, apparent metabolisable energy and ileal digestibility of nitrogen and starch in broilers. From 0 to 9 days of age, all birds were offered a common starter diet. Broiler grower (Days 10–21) and finisher (Days 22–42) diets, based on maize, were formulated and then allocated to the four different treatments. All diets were steam-conditioned at 60°C before pelleting. In grower diets, increasing pellet diameter and pellet length reduced (P 0.05) by main effects or the interaction. In grower and finisher diets, increments in pellet durability index and pellet hardness with increasing pellet length were greater in pellets with a 3-mm diameter than those with a 4.76-mm diameter. During the grower period (Days 10–21), birds fed the 3-mm-diameter pellets had lower (P 0.05) for weight gain, feed intake and feed per gain. Increasing pellet diameter from 3 to 4.76 mm decreased (P 0.05) for the coefficient of ileal apparent digestibility of nitrogen. Increasing pellet length from 3 to 6 mm decreased (P 0.05). Overall, when low conditioning temperatures are used to optimise nutrient availability, small diameter die holes and longer pellet lengths can favour creating high physical quality pellets. The present study also showed that feeding lower diameter pellets to broilers during the grower period (Days 10–21) only improved feed per gain, a response which disappeared as the birds grew older.

Influence of pellet diameter and length on the quality of pellets and performance, nutrient utilisation and digestive tract development of broilers fed on wheat-based diets

1. The influence of pellet diameter and length on the quality of pellets and performance, nutrient utilisation and digestive tract development of broilers given wheat-based diets was examined from 10 to 42 d of age. The experimental design was a 2 × 2 factorial arrangement of treatments evaluating two pellet diameters (3 and 4.76 mm) and two pellet lengths (3 and 6 mm). From 0 to 9 d of age, all birds were offered a common starter diet pelleted with a 3-mm diameter die and 3-mm length. Broiler grower (d 10 to 21) and finisher (d 22 to 42) diets, based on wheat, were formulated and then subjected to the 4 different treatments. 2. In grower diets, increasing pellet diameter and pellet length reduced the gelatinised starch (GS) content of the diets. In finisher diets, GS content of 3-mm diameter pellets did not change with increasing pellet length but decreased in 4.76-mm diameter pellets. 3. In grower and finisher diets, increments in intact pellet weight, pellet durability index and pellet hardness with increasing pellet length were greater in 3-mm diameter pellets than those with 4.76-mm diameter. 4. Increasing pellet length from 3 to 6 mm increased apparent metabolisable energy values. Neither the interaction nor main effects were significant for the ileal digestibility of nitrogen and starch. 5. During the grower period (d 10 to 21), birds given pellets of 6-mm length had greater body-weight gain than those given 3-mm length pellets. Feeding 6-mm length pellets decreased feed per body-weight gain compared to 3-mm length pellets. During the finisher (d 22 to 42) and whole grow-out (d 10 to 42) periods, while different pellet lengths had no effect on feed per body-weight gain values at 3-mm pellet diameter, increasing the pellet length decreased feed per body-weight gain at 4.76-mm pellet diameter. 6. Increasing pellet diameter and pellet length reduced the relative length of duodenum. Birds given 3-mm diameter pellets had heavier proventriculus compared to those given 4.76-mm diameter pellets. 7. Overall, the data suggest that increasing the pellet length from 3 to 6 mm improved the body-weight gain and feed per body-weight gain during the grower period (d 10 to 21). While the positive effect on body-weight gain disappeared as the birds grew older, improvements in feed per body-weight gain were maintained over the finisher and whole grow-out periods only in 4.76-mm diameter pellets. Small diameter die holes and longer pellet lengths may be considered as potential manipulations to manufacture high-quality pellets under low conditioning temperatures.

Particle size and feed form in broiler diets: impact on gastrointestinal tract development and gut health

The importance of feed particle size, as a tool to optimise the utilisation of feed and improve production efficiency in broilers, has attracted increased attention in recent years. Particle size reduction is widely believed to enhance the access of digestive enzymes to substrates because of the increased surface area of feed particles. Fine particles can negatively affect the development of fore-gut (proventriculus and gizzard), which plays an important role in intestinal health and nutrient utilisation. A well-developed fore-gut can be achieved by feeding coarse particles which is associated with improvements in gut motility and health. However, the results of studies considering the effect of feed particle size on upper gastrointestinal tract development have been inconclusive, because of the confounding effects of feed form (mash vs. pellets). Feed particle size influences the development of gastrointestinal tract and bird performance to a greater extent when the broilers are fed mash than pelleted diets. Particle size-reducing properties of the pelleting process may result in suboptimal gizzard development and changes in the intestinal morphology and microbiota profile.

Influence of Palm Kernel Meal Inclusion and Exogenous Enzyme Supplementation on Growth Performance, Energy Utilization, and Nutrient Digestibility in Young Broilers

The objective of the present study was to investigate the influence of palm kernel meal (PKM) inclusion and exogenous enzyme supplementation on growth performance, nitrogen-corrected apparent metabolizable energy (AMEn), coefficient of apparent ileal digestibility (CAID) and total tract retention of nutrients in young broilers fed corn-based diets. Four inclusion levels of PKM (no PKM [PKM0], 8% [PKM8], 16% [PKM16], and 24% [PKM24]) and two enzyme additions were evaluated in a 4×2 factorial arrangement of treatments. A total of 384, one-d-old male broilers (Ross 308) were individually weighed and allocated to 48 cages (eight broilers/cage), and cages were randomly assigned to eight dietary treatments. Results indicated that the inclusion of 8% and 16% PKM increased (p<0.05) the weight gain compared to the PKM0 diet. Birds fed the PKM8 diets had the highest (p<0.05) feed intake. Weight gain and feed intake were severely reduced (p<0.05) by feeding the PKM24 diet. Enzyme supplementation increased weight gain (p<0.05), independent of PKM inclusion level. In PKM0 and PKM8 diets, enzyme addition significantly (p<0.05) lowered feed conversion ratio (FCR); whereas enzyme addition had no effect on FCR of birds fed PKM16 and PKM24 diets. In PKM0 and PKM16 diets, enzyme addition significantly (p<0.05) increased CAID of nitrogen and energy but had no effect in the PKM8 and PKM24 diets. Inclusion of PKM into the basal diet, irrespective of inclusion level, enhanced (p<0.05) starch and fat digestibility. Inclusion of PKM at 16% and 24% resulted in similar CAID of neutral detergent fiber (NDF) but higher (p<0.05) than that of the PKM0 and PKM8 diets. Enzyme addition, regardless of the level of PKM inclusion, significantly (p<0.05) increased CAID of NDF. There was a significant (p<0.05) decrease in AMEn with PKM inclusion of 24%. The present data suggest that inclusion of PKM in broiler diets could be optimized if PKM-containing diets are formulated based on digestible amino acid contents and supplemented with exogenous enzymes. If amino acid digestibility and AME of PKM considered in the formulation, it can be included in broiler diets up to 16% with no deleterious effects on growth performance.

Influence of pellet length changes at 4, 5 and 6 weeks of age and two pellet diameters on growth performance and carcass characteristics of broiler finishers

A 2 × 4 factorial arrangement of treatments was used to evaluate the effects of two pellet diameters and four pellet length–week combinations on the growth performance and carcass characteristics of broilers (days 22 to 42). A broiler finisher diet based on wheat and soybean meal was formulated. Pelleted diets were manufactured in four different sizes: (i) 3 mm diameter (D3) and 7 mm length (L7), (ii) D3, 9 mm length (L9), (iii) 4.76 mm diameter (D4.76), L7, (iv) D4.76, L9. The four pellet sizes were then used to develop eight feeding treatments: (i) D3 and L7 pellets during weeks 4, 5, and 6 (L777); (ii) D3 and L7 during weeks 4 and 5, and L9 during week 6 (L779); (iii) D3 and L7 during week 4, and L9 during weeks 5 and 6 (L799); (iv) D3 and L9 during weeks 4, 5, and 6 (L999); (v) D4.76 and L7 during weeks 4, 5 and 6 (L777); (vi) D4.76 and L7 during weeks 4 and 5, and L9 during week 6 (L779); (vii) D4.76 and L7 during week 4, and L9 during weeks 5 and 6 (L799); (viii) D4.76 and L9 during weeks 4, 5, and 6 (L999). Increasing the pellet length from 7 to 9 mm increased pellet hardness at both pellet diameters and improved the pellet durability index in D3 pellets but had no effect in D4.76 pellets. Over the whole trial period (days 22–42), birds fed D3 pellets were heavier and had lower feed per gain and higher carcass yield than those fed D4.76 pellets. Feeding length–week combination L999 resulted in lower carcass yield than L777, L779, and L799. Overall, it is concluded that whilst broiler finishers express a preference for a smaller pellet diameter, there is no negative effect of pellet length (up to 9 mm) on performance parameters even when offered as early as day 21.

Age-related energy values of meat and bone meal for broiler chickens

ABSTRACT Six hundred and eighty‐four male Ross 308 broiler chicks were used to test the null hypothesis that post hatching age between day 0 and 21 does not affect utilization of energy in meat and bone meal (MBM). There were 6 replicate cages in each of 12 treatments consisting of 3 test diets (0, 40, or 80 g MBM/kg diets) at 4 feeding ages post hatching (day 0 to 7, 6 to 11, 10 to 16, or 15 to 21 post hatching) for a total of 72 cages in a randomized complete block design. Birds were assigned to the 12 treatments on day 0, fed a standard starter diet until they were switched to the test diets on day 0, 6, 10, or 15, and the number of birds per cage for day 0 to 7, 6 to 11, 10 to 16, or 15 to 21 were 12, 10, 8, or 8, respectively. Excreta were collected during the last 3 days of each feeding age post hatching and ileal digesta on the last day of each age. There was no interaction between dietary MBM level and feeding age post hatching for any of the response criteria. Weight gain and gain‐to‐feed ratio improved linearly (P < 0.001) with increasing dietary MBM and, expectedly, there was an increase (P < 0.001) in weight gain and a reduction (P < 0.001) in gain‐to‐feed ratio with bird feeding age post hatching. Ileal digestible energy (IDE), apparent metabolizable energy (AME), and nitrogen‐corrected AME (AMEn) of the diet linearly increased (P < 0.001) with increasing dietary MBM. There were linear increases in dietary IDE (P < 0.05), AME (P < 0.001), and AMEn (P < 0.001) with bird feeding age post hatching. The IDE, ME, and MEn of MBM were determined by the regression procedure. During day 0 to 7, 6 to 11, 10 to 16, or 15 to 21, energy values increased (P < 0.05) with age and the respective IDE of MBM were 2.852, 2.962, 2.927, or 2.959 kcal/g DM. Corresponding ME of MBM were 2.909, 3.125, 3.083, or 3.075 kcal/g DM and those of MEn were 2.687, 2.887, 2.839, or 2.845 kcal/g DM. These results show that energy values of MBM increase with age post hatching and suggest the same energy value of MBM should not be used in formulating diets of broiler chickens during the first 3 weeks post hatching.