A central composite design (CCD) study was conducted to understand the relationship among dietary branched chain amino acid (BCAA) ratios and expression of proteins related to glucose and energy metabolism in the jejunum of broilers. A total of 2,592 d-old Ross 344 × 708 male broilers were randomly placed in 144 floor pens. Each pen received 1 of 15 dietary treatments in a 23 CCD with 6 center points from 20 to 35 d of age, varying in digestible ratios of isoleucine:lysine (Ile:Lys; 52 to 75), valine:lysine (Val:Lys; 64 to 87), and leucine:lysine (Leu:Lys; 110 to 185). On d 35, one bird per pen was selected, euthanized, and jejunum tissue samples were collected for protein extraction and proteomic analysis via data independent acquisition protein sequencing with a timsTOF Pro 2 LC/MS/MS and Spectronaut 15 software. Glycogen synthase kinase-3 beta (GSK3A), dihydrolipoamide acetyltransferase (PDHX), AMP deaminase (AMPD3), succinyl-CoA-Ketoacid-coenzyme A transferase (OXCT1), adipocyte-type fatty acid-binding protein (FABP4), and O-N-acetylglucosamine transferase subunit p110 (OGT) were identified and quantified. Protein quantification data were analyzed as a CCD using the RSREG procedure of SAS v. 9.4 with significance declared at P ≤ 0.10. The surface response model for OGT expression was significant (P = 0.028; R2 = 0.20). However, the models for GSK3A, PDHX, AMPD3, OXCT1, and FABP4 were not significant (P ≥ 0.1356) and the R2 values ≤ 0.15 did not allow for prediction of protein expression means. The coefficients for the Val:Lys ratio effect on PDHX (P = 0.09), the Leu:Lys ratio effect on PDHX (P = 0.0716) and OGT (P = 0.0763) protein expression were significant. In addition, the Ile:Lys × Leu:Lys interaction for PDHX (P = 0.0415) and the cross-product coefficient for Ile:Lys ratio effect on OGT (P = 0.0535) pro- tein expression were also significant. The expression of OGT was affected by the Leu:Lys ratio (P = 0.0511) and the Ile:Lys ratio altered GSK3A (P = 0.0633) expression.
Article Quarter: FY23 Q2
Nitrogen correction of true metabolizable energy values for poultry feed ingredients
The apparent metabolizable energy (AME) and true metabolizable energy (TME) assays of poultry feed ingredients have traditionally been nitrogen (N) corrected to yield AMEn or TMEn. By correcting to zero N retention in the AMEn bioassay all feed ingredient results are directly comparable to one another. Roosters for the TMEn bioassay are fasted for 24 hours prior to precision feeding of the test ingredient which places them in a negative N balance. The N correction for the TMEn assay was utilized to avoid an overestimation of the endogenous energy correction. In the original published research conducted over 40 years ago, roosters remained in a negative N balance when fed test ingredients and the N correction resulted in TMEn values that were 1 to 14% lower than their corresponding TME values. In the current research N retention, TME and TMEn were determined on over 700 ingredient samples to determine if the original findings on N retention and correction were still appropriate. For all ingredients tested, a positive correlation (P < 0.0001) existed between N balance and the TME minus TMEn value. Unlike the original research, over 15% of the samples tested had a positive N balance. These samples were almost exclusively animal by-products (ABP) such as feather and meat and bone meals. About 45% of the tested ABP had a negative N balance. There was a positive (P < 0.0001) correlation between total digestible amino acid content and N balance in the ABP samples. For 68 of the ABP samples the TMEn value was decreased by 10% or greater from the TME value. However, unlike the original research, N correction increased the TMEn value relative to its TME value in 10% of the samples. Roosters fed these samples had a negative N balance that exceeded that of the unfed endogenous control roosters, and the samples such as soy and rice hulls, were low in protein and/or high in fiber. For some of these samples the N correction inflated the TMEn value by over 20%.
Evaluation of dietary nutrient reduction on broiler chicken growth performance, carcass characteristics, and breast meat quality defects
Numerous nutritional intervention strategies have been investigated with the aim of eliminating the breast meat quality defects, Wooden Breast (WB) and White Striping (WS). Yet, the etiology of these defects is still unknown. Previously, feeding diets in meal form with a 30% reduction in metabolizable energy (ME), digestible Lys (dLys), and digestible Met (dMet) during the starter diet phase decreased WB incidence, BW, BWG in birds fed to d 21. Thus, the objective here was to develop a feeding model resulting in market-weight broilers with a variety of WB and WS scores. A corn and soybean meal-based commercial diet served as the control (C) and the second diet was formulated with a 30% reduction in ME, dLys, and dMet (R). The C diets were fed as crumbles in the starter (d 0 to 15) and grower (d 16 to 29) phases and were pelleted for the finisher (d 29 to 40) phase, whereas R diets were fed in meal form in all feeding phases. Feeding the C and R diets during the 3 feeding phases produced the following 4 treatments: CCC, RCC, RRC, and RRR. Male, Ross 708 ́ Yield Plus chicks (n = 1,440) were randomly allotted to 1 of 4 treatments, blocked by location, and reared in floor pens (30 birds per pen) until processing on d 42 when carcass weights and part yields, and incidence and severity of WB and WS were assessed. Data were analyzed as a 1-way ANOVA using SAS PROC GLIMMIX and a complete pairwise mean comparison analysis was done using the PDIFF option at P ≤ 0.05. As expected, BWG and FCR worsened the more phases the broilers were fed the R diet (P < 0.0001). Carcass, breast, tender, wing, thigh, and drum weights and yields were lowest in the RRR-fed broilers, highest in CCC-fed broilers, with the RRC and RCC-fed broilers being intermediate (P < 0.0001). The incidence and severity of both WB and WS were lowest in the RRR-fed broilers compared with all other treatments (P < 0.0001); however, it is important to note that this feeding strategy did not eliminate either breast meat quality defect.
Comparative impact of incorporation of specialty protein feedstuffs and antibiotic growth promoters in broiler chicken starter feeding program on growth performance through to 49 days of age
Specialty highly digestible protein feedstuffs (SPF) and antibiotic growth promoters (AGP) are often added to partially replace regular soybean meal (SBM) in starter phase. However, there is limited comparative data on the effectiveness of these approaches on lifetime growth performance (GP). We conducted two experiments (Exp.) to assess the impact of inclusion of SPF or AGP in the starter on GP through to 49 d of age. Six iso-caloric and -nitrogenous starter (d 0-10) diets were formulated to meet or exceed specifications. Diets were: 1) NC, corn and SBM, 2) PC, NC+ AGP (Bacitracin Methylene Disalicylate and Narasin), 3) FSBM, NC+ further processed SBM, 4) SPC, NC+ soy protein concentrate, 5) PM, NC+ pork meal and 6) BSFLM, NC+ black soldier fly larvae meal. Day old Ross x Ross 708 males were placed in 48 cages (6 birds/cage) for Exp. 1 and 48 floor pens (35 birds/pen) in four rooms (block) for Exp. 2. Test diets were fed for 10 days and birds in Exp. 2 transitioned to a common diet. The BW, feed intake (FI) and mortality were monitored for calculation of BWG and FCR. A sample of birds were necropsied on d 10, 28 and 49 in Exp. 2 for visceral organs and breast weight. For statistical analyses, diet was the fixed effect in Exp. 1 whereas diet and block were fixed effects in Exp. 2 and LSmeans were separated using Tukey method. Crude protein in SBM, FSBM, SPC, PM and BSFLM was 48.4, 52.6, 71.6, 57.2 and 54.5% as fed, respectively. Birds fed PC, SPC and BSFLM tended (P= 0.09) to be heavier than NC birds at the end of Exp. 1 (d 10). In Exp. 2, birds fed PC and SPF had higher (P<0.001) starter BWG relative to NC birds. In the overall (d 0-49), birds fed PC had similar (P>0.05) d 49 BW and FI to birds fed SPF but higher (P≤0.02) than for birds fed NC diets. Day 49 BW was 3,759, 3,479, 3,664, 3,649, 3,739, and 3,735 for PC, NC, FSBM, SPC, PM and BSFLM, respectively (P=0.003). The FCR and breast yield was not affected by the diet. On d 10, birds fed SPC and PM had heavier d 10 liver than NC birds whereas birds fed FSBM had heavier proventriculus than PC, SPC, and BSFLM birds (P=0.01).
Nutrient, starch and energy utilization along the digestive tract and their impacts on cecal short chain fatty acid production in broiler chickens receiving different types and graded dietary levels of resistant starches
A total of 480 Cobb 500 male broiler chicks were used in a 21-day study to investigate the site and extent of nutrient, starch, and energy utilization and their effects on cecal short-chain fatty acids (SCFA) profile in broiler chickens receiving different types and graded levels of resistant starches (RS).The birds were allocated to 10 treatments in a 3×3+1 factorial arrangement comprising a corn-soybean meal control diet and the factors: 3 RS types (RST): banana starch (BS), raw potato starch (RPS) and high- amylose corn starch (HCS); each at 3 levels (RSL) 25, 50 or 100 g/kg. On d 21, jejunal and ileal digesta, excreta, and cecal content were collected for digestibility, total tract nutrient, starch, energy utilization, and cecal SCFA profile. RST × RSL was significant (P < 0.01) for total tract DM and N retention, AME, and AMEn. Overall, DM, N and starch retention, AME, and AMEn were greater (P < 0.05) for the control than other diets. In- creasing RSL decreased (P < 0.05) DM, N and starch retention, AME and AMEn for BS and RPS, but increased all these for HCS except for starch retention which was not different at all HCS levels. There was significant (P < 0.01) RST × RSL for ileal N and starch digestibility. Birds receiving RS diets had ileal N digestibility comparable to the control diet whereas birds receiving 50 g/kg BS had lower (P < 0.01) N digestibility. Ileal starch digestibility was lower (P < 0.01) for birds receiving RS diets compared with the control. Increasing RSL decreased (P < 0.01) ileal starch digestibility for BS and RPS but had no effect on HCS. RST × RSL was significant (P < 0.01) for jejunal starch digestibility. Birds receiving RS diets had (P < 0.01) lower starch digestibility than control except for HCS. Jejunal starch digestibility decreased (P < 0.01) with increased RSL except for HCS. There was no RST × RSL nor significant RST effect for any SCFA measured. Birds receiving 100 g/kg RSL had greater (P < 0.05) acetate and total SCFA (P < 0.05) than those receiving 50 g/kg but comparable to other treatments and the control.
Relationship between viscosity of digesta and development of the gastrointestinal tract of broiler chickens
The objective of this study was to determine the effects of digesta viscos- ity on growth performance, apparent ileal digestibility (AID) of nutrients, metabolizable energy (ME) and N-corrected ME (MEn) of diets, organ parameters and intestinal modulation in broiler chickens. The experiment was designed as a randomized complete block design with body weight (BW) used as a blocking factor. On d 8, a total of 168 broiler chickens (186.8 ± 20.5 g) were allocated to 3 corn-soybean meal-based diets with increasing concentrations of carboxymethyl cellulose (CMC) – 0, 10, or 20 g/kg added at the expense of cornstarch from the basal diet. There were 8 replicate cages per dietary treatment with 7 birds per pen. Birds were euthanized on d 22 for sample collection. Data were analyzed using the GLM procedure of SAS. Orthogonal polynomial contrasts were used to estimate the linear and quadratic effects of CMC. The ileal and jejunal digesta viscosity linearly increased (P < 0.01) with dietary CMC addition. There was a linear reduction (P < 0.01) in the BW of birds on d 15 and 22 with CMC. Moreover, the BW gain and the gain-to-feed ratio of birds linearly reduced (P < 0.01) with CMC addition throughout the experimental period. With CMC inclusion, the duodenal, jejunal, and ileal length linearly increased (P < 0.05). The addition of CMC also linearly increased (P < 0.05) the relative weight of the ileum and proventriculus in birds. The AID of dry matter, nitrogen, ME, and MEn linearly decreased (P < 0.01) with CMC inclusion. In the jejunum, the digesta crude mucin quadratically reduced (P < 0.05). However, there was a tendency for a quadratic increase (P < 0.1) in the jejunal villus height and villus height to crypt depth ratio with CMC addition.
Evaluation of corn particle size on the growth performance, gut permeability, pellet quality, and litter moisture of turkey hens raised without antibiotics
An experiment was conducted to determine the effects of corn particle size (CPS) on turkey hen performance, intestinal permeability (IP), and litter dry matter. Hybrid turkey hens were housed in floor pens from 0 to 42d. Hens were fed a crumbled starter 1 (0 to 21d) and pelleted starter 2 (22 to 42d) diet. The experiment was a 2 x 2 factorial with diet phase (starter 1 and starter 2) and CPS (fine or coarse), resulting in 4 treatments of 18 replicates of 22 turkeys. Corn was manufactured using a hammermill with a 4.76 mm screen (581 μm; fine) or a 6.35 mm screen (964 μm; coarse). Pellet quality was determined using pellet durability index (PDI), modified pellet durability index (MPDI), and New Holmen Pellet Tester (NHPT). Body weight (BW) and feed offered and refused were measured on D0 and D42. Mortality corrected feed conversion ratio (FCRm) was calculated from 0 to 42 d of age. The IP was measured on D42 by orally gavaging one turkey per pen with 8.32 mg/kg of FITC-d dissolved in distilled water 1 h before blood collection. Blood was centrifuged to isolate serum. Litter dry matter content was measured on D42. Data were analyzed using JMP Pro 16.0 (P ≤ 0.05) and means were separated using Student’s t-test. Corn particle size did not impact the measured pellet quality variables (PDI, MPDI, and NHPT) in the starter 2 diets (P > 0.05). There were no interac- tions between dietary phase and CPS over the experiment. There was a main effect of BW over the starter 1 phase as hens fed fine corn resulted in increased FI (3.28 vs 3.22 kg/bd; P ≤ 0.01) and BW (2.49 vs 2.44 kg/ bd; P ≤ 0.01) compared to those fed coarse corn. Corn particle size did not alter FCRm (P > 0.05). The IP was not influenced by CPS in the starter 1 (P = 0.59) or starter 2 (P = 0.31) dietary phases when measured on D42. Litter dry matter content was not influenced by CPS of starter 1 (P = 0.13) or starter 2 (P = 0.62).
Evaluation of supplemental fat sources and pre-farrow essential fatty acid intake on lactating sow performance and essential fatty acid composition of colostrum, milk, and adipose tissue
A total of 91 sows (Line 241, DNA Genetics) were used to evaluate the effects of supplemental fat sources and essential fatty acid intake on sow farrowing performance, litter growth performance, and essential fatty acid composition of colostrum, milk, and adipose tissue. At approximately day 107 of gestation, sows were blocked by body weight and parity, then allotted to 1 of 5 experimental treatments as part of a 2 × 2 + 1 factorial arrangement. Experimental diets were corn-soybean meal-based with a control diet that contained no added fat or diets with 3% added fat as either beef tallow or soybean oil, with consumption of the added fat diets starting on day 107 or 112 of gestation and fed until weaning. Thus, sows were provided low essential fatty acids (EFA; as linoleic and α-linolenic acid) without supplemental fat or with beef tallow or high EFA with soybean oil. Sows were provided approximately 2.8 kg/d of their assigned lactation diet pre-farrow and then provided ad libitum access after parturition. Sows consuming diets with beef tallow had greater lactation ADFI (fat source, P = 0.030), but lower daily linoleic acid (LA) and α-linolenic acid (ALA) intake than sows that consumed diets with soybean oil (fat source, P < 0.001). Supplemental fat sources providing either low or high EFA did not influence litter growth performance (fat source, P > 0.05). Sows fed diets with beef tallow did not influence the LA composition of colostrum; however, lactation diets with high EFA provided by soybean oil on day 107 of gestation increased colostrum LA concentration compared to providing diets on day 112 of gestation (fat source × time, P = 0.084; time, P < 0.001). Additionally, regardless of pre-farrow timing, ALA concentration of colostrum increased when sows consumed diets with soybean oil compared to beef tallow (fat source, P < 0.001).
The effect of moderate energy and protein restriction during gilt development on changes in body weight and backfat depth and subsequent lactation performance
Eighty-eight gilts [initial body weight (BW) 49.8 ± 0.8 kg] were recruited to determine the effects of moderate energy and protein restriction during the development period on changes in BW and backfat depth (BF) and subsequent lactation performance. Gilts were randomly assigned to one of four feeding programs: 1) standard commercial diet fed ad libitum (CON), 2) standard commercial diet fed 10% or 3) 20% below ad libitum, or 4) a high–fiber diet fed ad libitum [2.5 times more fiber (neutral detergent fiber) than the commercial diet to dilute net energy and crude protein by approximately 20% and 13%, respectively; FIB]. The gilts were housed individually and received the feeding programs between 90 and 190 (breeding) d of age and standard gestation and lactation diets thereafter. Litters were standardized to 12 ± 1 pigs within 48 h of farrowing; weaning occurred at 20.0 ± 0.4 d of age. Gilts that received the 20% restricted program had lower overall average daily feed intake (ADFI) during the development period (2.64 ± 0.04 kg; P < 0.05) versus all other feeding programs and gilts that received the 10% restricted program had lower ADFI than FIB and CON, which were not different (2.96 vs. 3.44 and 3.47 ± 0.04 kg for 10%, FIB and CON, respectively; P < 0.05). Plasma free fatty acid (FFA) concentrations on day 180 of age were lower for gilts that received the 10% and 20% restricted programs compared to gilts that received the FIB and CON programs, which were not different (97 and 86 vs. 220 and 149 ± 29 µEq/L, respectively; P < 0.05). Plasma concentrations of glucose, urea, prolactin, and IGF-1 were not different among feeding programs on day 180 of age. At breeding, gilts that received the FIB and 10% programs had lower BW and BF versus CON (145.7 and 144.8 vs. 155.2 ± 0.9 kg and 14.4 and 14.8 vs. 16.5 ± 0.2 mm for BW and BF, respectively; P < 0.05) but greater BW than gilts that received the 20% restricted program (137.9 kg; P < 0.05). The BW and BF of gilts did not differ at the end of gestation or at weaning. The ADFI of sows during lactation and offspring birth weight and growth rate during lactation and the 5-wk nursery period were not influenced by gilt development feeding program.
