Salmonella is a major foodborne pathogen related to the consumption of poultry meat and is the leading cause of salmonellosis. Salmonella is known to transmit in poultry flocks both vertically and horizontally. However, there is a lack of knowledge on the sources of Salmonella in poultry live production systems, including hatchery, feed, water, environment-interior, and -exterior. A systematic review- meta-analysis was conducted to quantify potential sources of Salmonella during pre-harvest and their relative contributions to microbial risk of poultry meat. After applying exclusion criteria, 16,800 studies were identified from Google Scholar, and 39 relevant studies were included in the meta-analysis for relative contributions to Salmonella positivity on broilers. From the identified studies,the number of positive samples and sample size were included as quantitative data. Regions of study conducted (U.S. and non-U.S.) and sample source (contribution factor) were extracted from the studies. Sources of samples from the broiler live production section were further divided into excreta (e.g., excreta or cecal samples, or cloacal swabs), litter (e.g., litter, boot socks, or drag swabs), chicks, hatchery, water, feed, interior environment (e.g., rodents, darkling beetles, fan surfaces, feed trough or mice), exterior environment (e.g., water puddles, wild birds, soil, grass, or poultry house outside surface swabs). A generalized linear mixed model approach combined with logit transformation was used to stabilize the variance. Data analysis was conducted using R version 4.0.2 (R Core Team, 2021). Meat for package was used to generate the meta-analysis statistics (predicted prevalence and heterogeneity parameters) and Forest plots. The hatchery was the most significant contributor of Salmonella, with a prevalence of 48.5% (95% CI: 32.8 to 64.5%). Litter, feces, and the poultry house’s internal environment were the three other major contributing factors, with a prevalence of 25.4 (95% CI: 16.6 to 37.0%), 16.3 (95% CI: 10.6 to 24.3%) and 7.9% (95% CI: 3.0 to 18%), respectively. Poultry house external environment (4.7%), feed (4.8%), chicks (4.7%), and drinker water also contributed to Salmonella in the poultry environment.
Article Quarter: FY23 Q4
Prediction of the apparent metabolizable energy of soybean meal based on a rooster model
Several digestibility studies were conducted with roosters to evaluate apparent metabolizable energy (AMEn) of 36 soybean meal (SBM) samples collected globally between 2008 and 2020 to support more reliable prediction of SBM nutritive value while formulating. The studies were conducted with 36 intact roosters to evaluate energy, apparent fat and organic matter digestibility (dFAT; dOM) and 36 cecectomized roosters for apparent ileal crude protein digestibility (dCP). For each SBM, wet chemical composition was known, especially moisture, crude protein (CP), fat (FAT), crude fiber (CF), ash and nitrogen solubility in KOH (NKOH), a processing quality criterion. The SBM origins were mainly from South and North America, and India. The average AMEn value was 2602 kcal/kg as fed (n: 36; SD: 199 kcal; min: 2209 kcal; max: 2923 kcal). This is higher in comparison to main tables (WPSA, 1989; Rostagno, 2017; CVB, 2021) and our previous data obtained prior to 2008. To predict AMEn, we used a factorial equation corresponding to the sum of the energetic contribution of each digestible fraction: CP, FAT and carbohydrates (CHO). The digestible fraction was calculated by multiplying the content of the fraction by its digestibility. The digestibility of carbohydrates (dCHO) was calculated from dOM, dCP and dFAT. For SBM AMEn, the main contributor is the digestible protein (about 75%). The average dCP value was 89.8 % (n: 27; SD: 1.7; min: 86.2%; max: 93.1%). The dCP data were subject to two factors ANOVA (linear for CF and quadratic for NKOH). The dCP was correlated to CF and NKOH (n: 17; R2: 0.77; SE: 0.8; P < 0.01). The CF affected negatively dCP. According to our model, SBMs with higher CF content have a reduced protein digestibility by up to 2.0%. The lower (overprocessing) and the higher (underprocessing) NKOH values reduce dCP as well. Overprocessing can reduce protein digestibility by up to 5% (i.e. 100 kcal/kg). These data confirm that the best dCP was obtained with a NKOH range between 75 and 85% N. The average dFAT value was 79.8% (n: 33; SD: 16.9). The average dOM value was 63.1 % (n: 14; SD: 4.4). The higher the proportion of crude fiber in carbohydrates, the lower dCHO. The use of these three predictive digestibility coefficients makes it possible to reduce the variability of the prediction of SBM AMEn (n: 26; MSE: 161 kcal).
Prediction equations of energy and nutrient content and trypsin inhibitor activity in full-fat and solvent-extracted soybeans
We studied the effects of harvesting year and country of origin of the beans on the chemical composition, amino acid (AA) profile, and protein quality indicators of commercial soybean meals (SBM). In total, 312 samples of SBM from Argentina (ARG; n = 98), Brazil (BRA; n = 109), and United States of America (USA; n = 105) were collected at random from 2016 to 2022 (n = 55, 62, 27, 51, 34, 46, and 37, in each consecutive year) in crushing plants and feed mills at different locations of the European Union by specialized personnel. All chemical analyses were conducted by wet chemistry, except AA that were determined by NIRS. The data were analyzed as a completely randomized design with 21 treatments arranged as a 7 x 3 factorial with harvesting year and country of origin of the beans as main effects, using the MIXED procedure of SAS. The interactions between year crop and country of origin of the beans were significant for all the variables studied (P < 0.05) except EE. On 88% DM bases, harvest year affected all the variables on chemical composition and protein quality indicators of the SBM (P < 0.05). Independently of the country of origin of the beans, the average values per year for each variable ranged from 5.72 to 7.36% for sucrose, 45.9 to 47.3% for CP, 6.06 to 6.13% for Lys profile (% CP), and 1.79 to 2.64 mg/g for TIA (P < 0.001). Independently of the year of harvest, the moisture content of the ARG meals was lower than that of the BRA and the USA meals (11.2 vs. 11.6 vs. 11.8%; P < 0.01). BRA meals had more protein (47.3 vs. 46.1 vs. 46.1%) and raffinose (1.36 vs. 1.36 vs. 1.19%) but less sucrose (5.73 vs. 7.16 vs. 7.01%) and stachyose (4.22 vs. 4.64 vs. 4.91%) than the ARG and USA meals (P < 0.001). However, no differences among soybean origins were detected for EE or NDF. The content and profile of the AA, varied with the country of origin of the beans. In this respect, Lys profile (% CP) was better for the USA meals than for ARG and BRA meals (6.13 vs. 6.10 vs. 6.07%; P < 0.001). All protein quality indicators, except UA, were higher for the USA than for the South American meals (P < 0.001).
The digestible amino acid profile of soybean meal influences its productive energy (Arkansas Net Energy) value for broilers
Energy represents a major cost in feed formulation. Arkansas Net Energy (ArkNE) has shown soybean meal (SBM) provides more energy than reported with other energy systems. This study intended to develop a model to predict Ark NE of SBM based on its content of digestible nutrients, including the essential to non-essential digestible amino acid ratio (AAR), compared to apparent metabolizable (AME, AMEn) and classic net (CNE) energy. Four experiments (E1 to E4) were conducted 1-56 d in floor pens with diets formulated following Cobb 500 guidelines. Pelleted treatment diets (five-phase feeding program) included SBM dilutions with cellulose (E1) or corn (E2) and graded levels of oil (E3) or total digestible amino acids (E4). Body composition (Dual Energy X-Ray Absorptiometry), heat production (calorimetry chambers), performance, and digestible nutrients of 60 test diets were assessed. The ArkNE value of SBM was determined by regression (E1), and the digestible nutrient profiles of 4 SBM were characterized (E1 to E4). A database was built up (n=646), and data were analyzed in JMP using mixed models. A multiple linear model was obtained (E1 to E4) applying a stratified random data-splitting with a refitting approach to predict SBM ArkNE considering digestible crude protein (dCP, %), digestible fat (dEE, %), digestible starch (dST, %), and age (d) as fixed predictors: ArkNE (kcal/kg) = –134.7 + 81.09 dCP + 70.65 dEE + 36.7 dST – 13.76 age – 0.45 (age – 31.1548)2 (every predictor P<0.0001; adjR2 = 0.62). The model was validated. A coefficient to adjust the ArkNE for AAR was inferred from the model above and validated with a multiple linear mixed model that included AAR, dCP, and dEE as fixed predictors (AAR P=0.0178; E1 to E3; 96% accuracy). An AAR-optimized ArkNE model (ArkNEAAR; >92% accuracy) was obtained by combining the prediction model above and the correction factor: ArkNEAAR (kcal/kg) = ArkNE (0.95 AART/AARR + 0.05), being AART and AARR the AAR of the tested and a reference (AARR = 0.82) SBM, respectively. dCP% in SBM explained 95% of its ArkNE value. AME and AMEn were insensitive to dCP%, while CNE was less influenced by dCP% than ArkNE. Only ArkNE was consistently and positively correlated with AAR (P<0.0001), while AME and AMEn showed no consistent relationships. In contrast, CNE was negatively correlated with AAR (P=0.003). FCR and feed intake were correlated more with ArkNE than AME or CNE (>adjR2; < P value).
Productive energy (Arkansas Net Energy) is a better predictor of broiler feed intake and feed conversion ratio compared to metabolizable energy and classic net energy
Accurate prediction of feed intake (FI) and feed conversion ratio (FCR) is crucial for industry nutritionists. This study aimed to develop models to predict FI and FCR of broilers based on dietary Arkansas Net Energy (ArkNE), metabolizable (AME, AMEn), and classic net (CNE) energy values. Four experiments (E1 to E4) fed broilers a total of 60 pelleted diets within 1-56 d (four experiments, five phases each, three treatments per phase) following Cobb 500 guidelines. They included replacements of soybean meal with cellulose (E1) or corn (E2) and inclusion levels of oil (E3) or total digestible amino acids (E4). A total of 9600 birds were used (20 birds/pen, eight pens –the experimental unit– per treatment, three treatments per feeding phase, five phases assessed, four experiments). Body composition, heat production, and performance were assessed, and data analyzed in JMP (experiment = random factor) with a random data-splitting validation and refitting approach. Models were assessed (normality, homoscedasticity) and compared based on their precision (adjR2), error (RMSE), certainty (energy content P value), and consistency among experiments. The FI (g/bird/d) and FCR were natural log transformed (Ln) to reduce heteroscedasticity. ArkNE was the only system showing an inverse and consistent correlation with FI in all experiments (the higher the ArkNE, the lower the FI). The model to predict FI based on ArkNE (kcal/kg) as a predictor (P<0.001) was: Ln FI = – 2.77 – 0.000097 ArkNE + 0.038 age – 0.00159 (age – 31.1548)2 (adjR2=0.94). The FI was insensitive to the diet AME (P=0.377) or AMEn (P=0.427). The relationship between diet CNE and FI was not only inconsistent among studies but also positive in three of them and overall (the higher the CNE, the higher the FI). Models predicting FCR showed an equivalent pattern. ArkNE was the only system showing an inverse and consistent correlation with FCR among experiments. The model to predict FCR based on ArkNE as a predictor (P<0.001) was: Ln FCR = 0.6646 – 0.000225 ArkNE + 0.0112 age (adjR2=0.81). The relationship between FCR and diet AME or AMEn was inconsistent (positive in two studies; negative in two). The relationship between diet CNE and FCR was not only inconsistent among studies but also positive in three of them and overall. Indeed, a single model to predict Ln FCR, including ArkNE, AME (or AMEn), CNE, and age as predictors (adjR2=0.81; no multicollinearity among systems, VIF<4), showed a highly significant influence of the ArkNE (P<0.001) on the FCR but no influence of AME (P=0.768), AMEn (P=0.678), or CNE (P=0.662) on FCR. All models were validated.
The growth performance response of broiler chickens challenged with coccidiosis and receiving reduced-protein diets was not influenced by partly replacing SBM with alternative protein feedstuffs
This 42-d experiment investigated whether the growth performance response of broiler chickens receiving reduced-protein (RCP) diets and challenged with coccidiosis was influenced by partly replacing soybean meal (SBM) with alternative plant protein feedstuffs. A total of 1,176 male chicks received an adequate protein (ACP) starter diet from d0to8.Ond8,thebirdswereallocatedto4dietsina randomized complete block design. These were a corn-SBM ACP diet, corn-SBM RCP diet (RCP-SBM), RCP diet with 80 g/kg canola meal (RCP-CM), or RCP diet with 100g/kg cDDGS (RCP-cDDGS). All the RCP diets had 30 g/kg protein below the ACP diets in their respective phases (but similar standardized digestible amino acids and dEB). On d 15, each diet was further divided into two groups (with or without mixed Eimeria spp. challenge) for a total of 8 treatments (2×4 factorial), and 7 replicates each. Birds and feed were weighed on d 8, 14, 21, 28, and 42. A gut permeability test was done for one randomly selected bird/replicate on d 21 (6 d post-challenge) using FITC- dextran. Caecal content on d 42 were analyzed for short- chain fatty acids (SCFA) profile. In the pre-challenge phase (d 8 to 14), birds receiving the RCP-CM diet had lower weight gain than the ACP diet (P < 0.05). During the active Eimeria infection (0 to 7 d post-challenge), there was a significant diet × cocci (P < 0.05) where the feed intake was greater for birds receiving ACP than other treatments in non- challenged groups. In the challenged groups, birds receiving RCP-CM and RCP-cDDGS had greater (P < 0.05) feed intake than ACP and RCP-SBM diets. The challenged group had lower weight gain and higher FCR (P < 0.05) during this period. There was no diet × challenge on the overall (d 8 to 42) growth performance. The overall weight gain and d 42 body weight tended to be greater (P < 0.10) for ACP than the other treatments. During this period, Eimeria-challenged birds had lower weight gain and greater FCR (P < 0.05). The gut permeability test on d 21 (6 d post-challenge) showed no significant diet effect. There was significant diet × cocci (P < 0.05) for isobutyrate and isovalerate (P < 0.05) with no diet effect in the unchallenged group, whereas in the challenged group, RCP-CM had lower (P < 0.05) isobutyrate than ACP diet; and both RCP-SBM and RCP-CM treatments had lower (P < 0.05) isovalerate than ACP. The challenged group had lower (P < 0.05) acetate and butyrate than the non- challenged group.
Phosphorus digestibility and relative phosphorus bioavailability for soybean meals varying in particle size
Two experiments were conducted to determine P digestibility or bioavailability in dehulled solvent-extracted soybean meals (SBM) for 4 varying particle sizes. Experiment 1 was a CRD 4 x 2 factorial treatment arrangement of 4 mean SBM particle sizes and 2 dietary Ca levels with 6 replicate pens of 5 chicks for each dietary treatment. Experiment 2 was a CRD with 11 dietary treatments and 5 replicate pens of 4 chicks for each dietary treatment. In Experiment 1, Ross 308 chicks were fed 1 of 8 diets from 16-20 d of age. The diets were formulated to contain 0.2% or 0.75% Ca and 4 SBM with mean particle size of 466, 809, 1,174, or 1,577 μm. Ileal digesta and excreta were collected and analyzed for P. In Experiment 2, crossbred chicks (New Hampshire x Columbian) were fed 1 of 11 experimental diets from 8-22 d of age. The basal diet was a P- deficient-cornstarch-dextrose-SBM diet (0.14% nonphytate P). The remaining diets were the basal diet supplemented with 0.05 or 0.10% P from KH2PO4 or 12.5 or 25% of 1 of the 4 above SBM. The right tibia was collected from each euthanized chick for bone ash analysis. Data for both experiments were analyzed using the GLM procedure in SAS. Differences among treatments were considered significant at P<0.05. For Experiment 1, a 4 x 2 factorial analysis was used with 4 SBM particle sizes and 2 dietary Ca levels. For Experiment 2, the slope-ratio method was used to determine the bioavailability of the P in the 4 SBM relative to the P in KH2PO4 using the regression coefficients obtained from multiple regression of tibia bone ash regressed on supplemental P intake from KH2PO4 or the 4 SBM. Bioavailability values of the P in the SBM were calculated relative to KH2PO4 with bioavailability of P in KH2PO4 set at 100%.Ileal P digestibility was not affected by SBM particle size when dietary Ca was 0.2%. At 0.75% dietary Ca, the 1,577 μm SBM yielded the highest ileal P digestibility (65%) and was different (P<0.05) from the other SBM (53%). Chicks fed diets containing 0.2% Ca had higher (P<0.05) ileal P digestibility (88%) and excreta P retention (57%) compared with chicks fed diets containing 0.75% Ca (56% and 42%, respectively). In Experiment 2, the 1,577 μm SBM yielded the highest bioavailability (30%) which was higher (P<0.05) than that for 466 μm SBM (20%).
Elevating branched-chain amino acids beyond the recommended requirements may have a negative impact on the performance of broilers fed reduced crude protein diets
This study aimed to evaluate the impact of branched-chain amino acid (BCAA) levels above the recommended values on the performance of broilers fed reduced crude protein (RCP) diets with different energy densities. A Box-Behnken design was used comprising of three factors: net energy (NE, 9.0; 9.7 or 10.4 MJ/kg), BCAA (0%, 20% or 40% above the recommended requirements), and crude protein (CP, 15%, 17% or 19%). Thus, 13 wheat-barley-based diets were formulated in three forms: mash, crumbles, or a combination of mash and crumbles. A total of 1092 as-hatched Cobb 500 Elevating branched-chain amino acids beyond the recommended requirements may have a negative impact on the performance of broilers fed reduced crude protein diets broilers was used, with 7 replicates per treatment and 12 birds per replicate. Diets were offered as a common starter diet (d0 – 8), a common grower diet (d9 – 18), and test finisher diets (d19 – 35). The growth performance was evaluated by weighing the birds and feeds on d19, 28 and 35. Data were statistically analysed utilising the response surface of the JMP fit Linear Regression Models. The male percentage was used as a covariate, and the feed form was incorporated in the model to account for its impact. The study presents the results from d19 – 35. The significant interactions between factors (CP × NE and CP × BCAA) were fixed at 0% excess BCAA and 9.7 MJ/kg NE, respectively. The results revealed significant interactions on weight gain (WG) between CP and NE (P < 0.001) and between CP and BCAA (P < 0.0001). The CP × NE interaction indicated that birds fed diets with high NE densities had greater WG when they were fed high crude protein (HCP) diets. When fed RCP diets, there was no difference in WG between birds fed low and high NE density diets. The CP × BCAA interaction showed that birds offered diets containing high levels of BCAA showed a decrease in WG when they were fed RCP diets, as compared to those supplemented with 0% additional BCAA. In diets with HCP however, there was no effect on WG by the BCAA levels. The interactions on feed intake (FI) were also noted (CP × NE, P < 0.01 and CP × BCAA, P < 0.0001) showing a similar pattern as WG. A CP × BCAA interaction (P < 0.0001) was observed in relation to feed conversion ratio (FCR). This interaction indicated that 4% additional BCAA supplementation resulted in higher FCR in RCP-diets compared to 0% additional BCAA, while BCAA levels did not affect FCR in HCP diets.
Correlations between chemical composition and in vivo AMEn and ileal digestibility of amino acids of soybean meals of different origins in broilers
The objective of this research was to study the correlations among the chemical composition, protein quality, and AMEn content and standardized ileal digestibility (SID) of CP and amino acids (AA) determined in vivo in 21-d old broilers of soybean meal (SBM) samples from Argentina, Brazil, and USA. The samples (n= 9 per country) were collected at random in Europe and analyzed for main components (CP, AA, ether extract, fiber fraction, sucrose, stachyose, raffinose, and minerals), protein quality indicators [(urease activity, KOH solubility, protein dispersibility index, trypsin inhibitor activity (TIA)], and reactive Lys, using the homoarginine and furosine procedures. In addition, protein digestibility was determined in vitro, using 3 published methodologies based on pepsin and pancreatin. Broilers received a commercial corn-SBM diet in mash form from 0 to 16 d of age followed by the experimental diets which resulted from the combination of 53% of a N-free diet and 47% of the SBM tested, as the unique source of N. Each of the 27 SBM samples was replicated 6 times and the experimental unit was a cage with 8 broilers. Data were analyzed as a completely randomized design with origin of the SBM as main effect. The Pearson correlation coefficient (r) among the key variables studied, was determined using the CORR procedure of SAS. Numerous correlations between in vivo data and chemical composition of the SBM were detected and therefore, only those most relevant for the industry are discussed. Independent of the origin of beans, the AMEn contents of the SBM were positively correlated with the SID of CP (r = 0.523; P < 0.01), Lys (r = 0.492; P < 0.01), and the sum of five (Lys, Met, Cys, Thr, and Trp) key AA (r = 0.543; P < 0.01). Also, positive correlations between AMEn and reactive Lys (% Lys) determined by the homoarginine procedure (r = 0.526; P < 0.01), and between the SID of CP and key main protein quality indicators [PDI (r = 0.403; P < 0.05), TIA (r = 0.360; P < 0.10), and KOH (r = 0.324; P < 0.10)] were observed. Also, significant correlations between the SID of CP and Lys and reactive Lys (% Lys) of the SBM using the homoarginine procedure, were detected (r= 0.553 and 0.599; P < 0.01). However, no significant correlations between in vivo SID and in vitro CP digestibility were observed.
Effect of particle size of the soybean meal and fiber inclusion in the diet on growth performance, nutrient retention, and gastrointestinal tract traits of broilers from 0 to 42 days of age
This research evaluated the effects of the mean particle size (MPS) of soybean meal (SBM) and the inclusion of fiber in the diet on growth performance, total tract apparent retention (TTAR) of nutrients, and gastrointestinal tract (GIT) development in broilers from 0 to 42 d of age. The experiment was completely randomized with 8 treatments organized as a 2 × 4 factorial with 2 MPS of the SBM (coarse; 1,385 μm vs. micronized; 170 μm) and 4 diets that varied in the source of fiber used [control vs. 3% of oat hulls (OH), soy hulls (SH), and sugar beet pulp (SBP)] as main effects. The experiment had 2 feeding phases (0 to 21 and 22 to 42 d), in which the control diets (based on rice and SBM) varied exclusively in the MPS of the SBM used (coarse vs micronized). The experimental diets resulted from the dilution (wt:wt) of the control diets with 3% OH, SH, or SBP, respectively. Each treatment was replicated 6 times and the experimental unit was a floor pen with 20 chicks. Growth performance [(BW gain, feed intake (FI), and feed conversion ratio (FCR)] data are presented by feeding phase and cumulatively. TTAR of DM, OM, CP, and the AMEn of the diets was determined at 21 d of age. GIT traits were evaluated at 21 and 42 d of age. Data were analyzed as a completely randomized design with MPS of the SBM and fiber source inclusion as main effects, using the MIXED procedure of SAS. From 0 to 42 d of age, FCR was better for broilers fed micronized SBM than for broilers fed coarsely ground SBM (P < 0.05). Particle size of the SBM did not affect nutrient digestibility. In relative terms (% BW), the full proventriculus and gizzard were heavier in birds fed the coarse SBM at both ages (P < 0.05). At 42 d of age, gizzard pH was lower for the coarse than for the micronized SBM (P < 0.05). Fiber inclusion increased FI (P < 0.05) but did not affect energy conversion ratio. Birds fed OH ate more feed than birds fed the control diet, with birds fed SH and SBP being in an intermediate position (P < 0.05). Fiber inclusion did not affect nutrient digestibility. In relative terms (% BW) the inclusion of extra fiber in the diet increased the weight of the empty gizzard, an effect that was more pronounced with OH than with SH or SBP at both ages (P < 0.05 for the interaction). Also, irrespectively of the source, fiber inclusion reduced gizzard pH at both ages (P < 0.01).
