An accurate feed formulation is essential for optimizing feed efficiency and minimizing feed cost for swine and poultry production. Because energy and amino acid (AA) account for the major cost of swine and poultry diets, a precise determination of the availability of energy and AA in feedstuffs is essential for accurate diet formulations. Therefore, the methodology for determining the availability of energy and AA should be carefully selected. The total collection and index methods are 2 major procedures for estimating the availability of energy and AA in feedstuffs for swine and poultry diets. The total collection method is based on the laborious production of quantitative records of feed intake and output, whereas the index method can avoid the laborious work, but greatly relies on accurate chemical analysis of index compound. The direct method, in which the test feedstuff in a diet is the sole source of the component of interest, is widely used to determine the digestibility of nutritional components in feedstuffs. In some cases, however, it may be necessary to formulate a basal diet and a test diet in which a portion of the basal diet is replaced by the feed ingredient to be tested because of poor palatability and low level of the interested component in the test ingredients. For the digestibility of AA, due to the confounding effect on AA composition of protein in feces by microorganisms in the hind gut, ileal digestibility rather than fecal digestibility has been preferred as the reliable method for estimating AA digestibility. Depending on the contribution of ileal endogenous AA losses in the ileal digestibility calculation, ileal digestibility estimates can be expressed as apparent, standardized, and true ileal digestibility, and are usually determined using the ileal cannulation method for pigs and the slaughter method for poultry. Among these digestibility estimates, the standardized ileal AA digestibility that corrects apparent ileal digestibility for basal endogenous AA losses, provides appropriate information for the formulation of swine and poultry diets. The total quantity of energy in feedstuffs can be partitioned into different components including gross energy (GE), digestible energy (DE), metabolizable energy (ME), and net energy based on the consideration of sequential energy losses during digestion and metabolism from GE in feeds. For swine, the total collection method is suggested for determining DE and ME in feedstuffs whereas for poultry the classical ME assay and the precision-fed method are applicable. Further investigation for the utilization of ME may be conducted by measuring either heat production or energy retention using indirect calorimetry or comparative slaughter method, respectively. This review provides information on the methodology used to determine accurate estimates of AA and energy availability for formulating swine and poultry diets.

An accurate assessment of moisture content in feed ingredients is important because moisture influences the nutritional evaluation of feedstuffs. The objective of this study was to evaluate various methods for moisture content determination. In Exp. 1, the weight loss on drying (LOD) of corn, soybean meal (SBM), distillers dried grains with solubles (DDGS), whey permeate, whey powder, spray-dried porcine plasma (SDPP), fish meal, and a mixed diet of these 7 ingredients were measured by oven drying at 135°C for 2 h. Additionally, the samples were dried at 105°C for 3, 6, 9, 12, or 15 h. The LOD contents of the DDGS, whey permeate, and whey powder measured by drying at 135°C for 2 h were greater than the values measured by drying at 105°C for 3 h (p<0.05). All samples except SDPP (p = 0.70) dried at 105°C for 6, 9, 12, or 15 h caused more LOD compared with the samples dried for at 105°C for 3 h (p<0.05). The LOD contents of the individual ingredients were additive when dried at 105°C regardless of drying time. In Exp. 2, moisture contents of corn, SBM, wheat, whey permeate, whey powder, lactose, and 2 sources of DDGS (DDGS1 and DDGS2) were measured by the Karl Fischer method, oven drying at 135°C for 2 h, and oven drying at 125°C, 115°C, 105°C, or 95°C for increasing drying time from 1 to 24 h. Drying samples at 135°C for 2 h resulted in higher moisture content in whey permeate (7.5% vs 3.0%), whey powder (7.7% vs 3.8%), DDGS1 (11.4% vs 7.5%), and DDGS2 (13.1% vs 8.8%) compared with the Karl Fischer method (p<0.05). Whey permeate and whey powder were considerably darkened as the drying time increased. In conclusion, drying samples at 135°C for 2 h is not appropriate for determining the moisture content in whey permeate, whey powder, or DDGS as well as the mixed diet containing these ingredients. The oven-drying method at 105°C for 5 to 6 h appears to be appropriate for whey permeate and whey powder, and at 105°C for 2 to 3 h for DDGS.

In the poultry industry, many efforts have been undertaken to further improve the growth performance of broilers and identification and modulation of body weight (BW)-related bacteria could be one of the strategies to improve productivity. However, studies regarding the relationship between microbiota and BW are scarce. The objective of the present study was to investigate the relationship between microbiota and BW in different sections of the gastrointestinal tract (GIT). A total of twenty 18-day-old birds were selected based on the BW, and samples were collected from the three different sections of the GIT, which included the crop, ileum and cecum. Bacterial genomic DNA was extracted from the samples, and the V4 region of 16S rRNA gene were amplified. Amplicons were sequenced on Illumina MiSeq, and microbial communities were analyzed by using QIIME. In principal coordinate analysis, bacterial communities were clustered into three groups, based on the sections of GIT. Several BW-related bacterial groups were identified from linear regression analysis. At the genus level, Streptococcus from the ileum as well as Akkermansia in both ileum and cecum, were negatively related to BW, whereas Bifidobacterium in the ileum and Lactococcus in the cecum showed a positive correlation. The results from the present study showed that particular bacterial communities in the GIT were related to BW, and the study has broadened the understanding of the intestinal microbial ecosystem in broiler chickens.

An experiment was conducted to determine the efficacy of mycotoxin sequestering agents for binding or degrading aflatoxin B1 (AFB1) and deoxynivalenol (DON) by anin vitromethod. Ten toxin binder products including 5 bentonite clays (bentonite A, B, C, D, and E), 2 cellulose products (cellulose A and B), a yeast cell wall, an activated charcoal, and a mixture product containing minerals, microorganisms, and phytogenic substances were used in this experiment. Anin vitroprocedure was used to mimic the digestive process in pigs. The binding ability for AFB1 of the cellulose products was less compared with the values of other sequestering products (p < 0.05). The percent adsorption of AFB1 by bentonite clays, cellulose products, yeast cell wall product, activated charcoal product, and the mixture product were 92.5 (average of 5 bentonite products), −13.5 (average of 2 cellulose products), 92.7, 100.2, and 96.6, respectively. The respective values for DON were 3.24, 11.6, 22.9, 14.4, and 4.3. In conclusion, most toxin sequestering agents used in the present study had potential to bind AFB1 rather than DON based on thein vitrostudy which simulated the pH condition of the gastrointestinal tract of pigs.

A total of 256 broiler chickens and 208 White Pekin ducks were used in a 5-d trial to test additivity of the apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA) in corn and soybean meal (SBM). A nitrogen-free diet was used for standardization of apparent digestibility. Two diets contained corn or SBM as the sole source of CP and AA. Another diet was prepared by mixing corn and SBM. Chromic oxide was included as an indigestible marker. Birds received a standard starter diet from d 1 to 21 and thereafter the 4 experimental diets for 5 d in a randomized complete block design. On d 26, digesta from the distal section of the ileum was collected. To test additivity of digestibility values, the difference between measured values in mixed diet and predicted values calculated with measured values in individual ingredients was examined. The estimated basal endogenous losses of N and AA were higher in ducks compared with broilers (P < 0.05). Regardless of species, the calculated proportion of basal endogenous losses of CP and AA in calculating SID was higher (P < 0.01) in corn than that in SBM. The measured AID of His, Leu, Lys, Met, Phe, Glu, Pro, and Tyr in mixed diets for broilers were higher than predicted values (P < 0.05), whereas measured and predicted SID did not differ except for Cys. For ducks, the differences between the measured and predicted AID were significant (P < 0.05) for CP and all AA except for 8 AA (Arg, Ile, Thr, Val, Asp, Gly, Pro, and Tyr). Similar to the result from broiler study, there was no difference between the predicted and measured SID of CP and all AA except for Cys. The results showed that AID of some AA for corn and SBM were not additive in the mixed diet, but SID values were additive irrespective of the ingredients and species used. Moreover, extent of difference between measured and predicted values in ducks were higher than that in broilers.

Kong, C., Lee, J. H. and Adeola, O. 2011. Supplementation of β-mannanase to starter and grower diets for broilers. Can. J. Anim. Sci. 91: 389–397. Two experiments were conducted to investigate the efficacy of β-mannanase on ileal nutrient digestibility, total tract utilization of dry matter (DM), N, energy, and apparent metabolizable energy (AME, exp. 1), and growth performance (exp. 2) of birds fed practical corn-soybean meal (SBM)-based diets. In each experiment, 192 male broilers were assigned to four diets arranged in a 2×2 factorial of energy level [corn-SBM-based diet that met or exceeded NRC nutrient requirements (AE) or low energy (LE) diet containing 100 kcal of ME kg⁻¹ less than the AE diet] and enzyme supplementation (with or without β-mannanase) for 21 d. Supplementing the diet with β-mannanase increased the birds’ apparent ileal DM digestibility of the experimental diets (P<0.05), whereas there was no effect of energy level. Neither β-mannanase supplementation nor energy level had any effect on apparent ileal digestibility of any of the amino acids. The interaction between enzyme and energy levels was not significant for any criteria measured in the excreta except for DM (P=0.05). Addition of β-mannanase improved (P<0.01) the apparent total tract utilization of DM and energy in the broilers, and there was the same trend (P=0.06) for N utilization. Supplementing the diet with β-mannanase also improved the AME and AMEn of diets by 4.6 and 5.0%, respectively. For all growth performance responses in exp. 2, the interaction between enzyme and energy levels was not significant. During the starter period (day 2 to 22 post-hatch), β-mannanase supplementation significantly (P<0.05) increased the body weight (BW) gain of birds. During the grower period (day 22 to 44 post-hatch) and for the overall period there was no significant difference in BW gain or feed intake of birds regardless of energy level and β-mannanase supplementation. There were no dietary effects on feed efficiency of birds during the starter and the grower periods, whereas the birds fed AE diets had higher feed efficiency (P<0.01) than the birds fed LE diets. The results indicate that supplementing with β-mannanase may improve gain and energy utilization of broilers, whereas it may not affect ileal amino acid digestibility.