•The multiple factors that can affect the intestinal health of poultry are reviewed.•Improving digestibility has a key role on intestinal health.•Grain drying and feed processing and quality effects ...on digestibility are highlighted.•Breeder gut health and incubation conditions effects on progeny are explained.•Water quality and housing conditions also affect gut health.
The intestinal health of poultry has broad implications for the systemic health of birds, animal welfare, the production efficiency of flocks, food safety, and environmental impact. The importance of this topic has grown over the past two decades and this was the focus of this workshop arranged to provide a forum for discussion and mutual learning by sharing experiences, scientific information and demonstrations of comparative effects of multiple factors that affect intestinal health under controlled conditions. This special issue is the product of that workshop.
This first paper reviews the multiple aspects that can affect the intestinal health of poultry, and individual factors are then addressed in more detail in subsequent papers. However, some factors, like breeder intestinal health, incubation conditions, early feeding, water quality, housing conditions, feedstuff quality, mycotoxin and rancidity, and grain drying will be discussed herein since will not be covered in detail elsewhere in the issue. The objective of this paper is to offer a great overview of intestinal health in poultry production and emphasize that a holistic approach is necessary when trying to minimize these dysbiosis and enteric diseases.
Stress factors during poultry production can evoke changes in gene transcription and protein synthesis in the hen oviduct and could affect the internal and external egg quality. Studies of relative ...gene expression require the identification of the most stable reference genes for the quantitative polymerase chain reaction (qPCR) to investigate the reproductive tissues' response in laying hens kept in different production systems. The objective of this study was to determine the most stable reference genes of the magnum tissues of laying hens housed in two different production systems. Hy‐Line Brown hens were reared under the same sanitary conditions until 15 weeks of age. Later on, they were transferred into two different production systems, conventional cage (CC) and cage free (CF), up to 82 weeks of age. At 50 and 60 weeks, a total of six hens from each production system were euthanized, and magnum samples were collected. The qPCR was used to determine the RNA transcription level of five reference genes, ACTB, 18S, GAPDH, MSX2 and HMBS. These genes were evaluated for transcript expression in magnum tissues by NormFinder, BestKeeper, geNorm and RefFinder software. The results indicated that the most stable gene in the CF housing system was HMBS in three of the algorithms and in the CC housing system was the 18S, and the best combination of reference genes was HMBS/GAPDH in CF and 18S/HMBS in CC. In conclusion, HMBS, 18S and GAPDH genes could be used together as reference genes for the normalization of the magnum tissues transcript expression of hens in CF and CC housing systems.
Stressor factors during poultry production can produce changes in gene transcription and protein synthesis on the hen oviduct. Studies of relative gene expression require the identification of the most stable reference genes. The aim of this study was to determine the most stable reference genes of the magnum tissues of laying hens housed in two different production systems for welfare studies.
Egg consumers worldwide have increased their concerns about laying hens' welfare and its impact on final egg product quality. This study compared the egg quality parameters under the conventional ...cage (CC) and cage-free (CF) egg production systems in the tropics. The study was conducted on a commercial farm in Colombia using Hy-Line Brown pullets, reared under the same conditions for the first 15 wks. At 16 wks, the hens were distributed into two housing systems, CC and CF, on the same farm. The hens were fed the same diet for each phase in both systems and feed intake varied slightly. Egg samples were collected every six wks, from 22 to 82 wks of age. A total of 3960 eggs were analyzed at 11 sampling times. Parameters such as albumen height, egg weight, yolk color, eggshell thickness, eggshell strength, and Haugh units were determined using a DET-6000 machine. At 22 and 82 wks, screening for
spp. status was conducted using environmental and egg samples. Additionally, at 34, 64, and 82 wks, yolk samples were obtained for fatty acid profiles and crude protein (CP) analysis. The data were analyzed in a completely randomized block design with repeated measures (11 times): mean separation by Student's
-test yolk pigmentation, Haugh Units, and albumen height (
< 0.001) were higher in the CF compared with the CC between 38 and 69 wks of age, and eggs at 63 and 82 wks (
< 0.05) were heavier in the CF compared to the CC. Likewise, eggs from the CC had better eggshell strength from 57 to 82 wks. In the egg yolk fatty acid profile at the 34th wk, the pentadecanoic, palmitic, and heptadecanoic acids had higher concentrations in the CF systems than the CC. At the 64th wk, the egg yolk fatty acids-lauric, myristic, and heptadecanoic-had higher concentrations in the CF; likewise, at the 82nd wk, egg yolks from the CC had higher concentrations of lauric, heptadecanoic, and nervonic fatty acids than the CF. The eggs and environmental samples were negative for
spp. throughout the whole production phase. These results indicated that the production system might impact internal and external egg quality measures, potentially due to various stressors, including environmental factors or behavior restrictions.
Low crude protein (CP) diets can reduce nitrogen (N) excretion and costs by increasing N utilization efficiency. Exogenous proteases may further improve protein digestibility in low CP diets. This ...study first evaluated in vitro the efficacy of a multiprotease on amino acid (AA) release from feedstuffs and broiler feed. Later, a broiler study evaluated the effect of feeding corn-soybean meal diets containing 3 CP levels (17, 19, and 21% CP) with supplementation on top of 0 or 2,400 U/kg multiprotease on chicken growth performance, total tract CP, and ileal AA digestibilities, and energy utilization. Ross 708 male chickens were placed in 42 cages and assigned to 6 treatments resulting from a 3 × 2 factorial arrangement. Three isocaloric basal diets were formulated to reduce CP, but all diets maintained digestible Lys:CP in 5.47% and the same ideal protein profile. Data were analyzed in a completely randomized design. On average, the multiprotease increased (P < 0.05) in vitro free AA release by 27.81% in most feedstuffs evaluated compared to the control. For broiler feed, 1,200 U/g multiprotease addition improved (P < 0.001) in vitro free AA release by 18.90%. This multiprotease showed interaction effects (P < 0.05) on chicken FCR, energy, and CP digestibility. As expected, BW at 24 d, BW gain, and FCR (8–24 d) worsened (P < 0.001) as dietary CP reduced from 21 to 17%, and multiprotease addition did not improve (P > 0.05) these parameters. BW gain decreased by 12.9% when N intake was reduced from 49.32 to 38.49 g/bird. Multiprotease supplementation improved (P < 0.01) AMEn by 71 kcal/kg, CP digestibility from 59.45 to 63.51%, ileal AA digestibility, and DM digestibility from 67.08 to 73.49%, but only in the 21% CP diet. No differences in ileal AA digestibility due to CP level (P > 0.05) were detected, except for Cys digestibility (P < 0.01). In conclusion, low CP diets reduced growth performance and improved N utilization but negatively affected energy utilization efficiency. Exogenous multiprotease supplementation improved AME, AMEn, protein, ileal AA, and DM digestibility in the 21% CP diet without significantly affecting growth performance.
Broiler live performance may be influenced by postharvest corn drying temperature, and results could depend on particle size after grinding. The supplementation with an exogenous amylase may improve ...performance parameters, but responses to enzymes are also affected by particle size. Two parallel experiments were conducted to evaluate the effects of hard-kernel corn dried at 2 temperatures (35°C and 120°C), ground at 2 particle sizes (coarse or fine), and 3 supplementation levels (0, 133, and 266 g ton-1) of an exogenous amylase on live performance, gastrointestinal organ development, energy utilization, and nutrient digestibility. Twelve dietary treatments resulting from a 2 × 2 × 3 factorial arrangement of drying temperature, particle size, and amylase supplementation were evaluated in both experiments. A total of 1,920 day-old male chicks were randomly allocated to 96 floor pens, while 480 chicks were distributed among 4 battery brooder units. Ileal and fecal samples were collected to determine energy utilization and nutrient digestibility using titanium dioxide as inert marker. At 42 D, organs were collected, and relative weight or length was determined. Data were analyzed using a three-way ANOVA in a randomized complete block design. Feeding fine corn-based diets showed improvements on live performance for both studies. At 40 D, supplementing 266 g ton-1 of amylase improved feed conversion ratio (P < 0.05) by 1 point compared to chickens that consumed nonsupplemented diets and feed with amylase at 133 g ton-1. Broilers fed coarse corn–based diets had heavier gizzard (P < 0.001) and liver (P < 0.05) than chickens that consumed fine corn-based diets. In addition, starch digestibility was improved by amylase (P < 0.05) at 133 g ton-1 and by feeding coarse corn-based diets (P = 0.06). For chicks raised in cages (16 D), AMEn was increased (P < 0.01) by amylase supplementation regardless of its inclusion level. In conclusion, drying temperature and particle size interactions influenced broiler live performance, gastrointestinal organ development, nutrient digestibility, and energy utilization, and these parameters were improved by supplementing amylase.
Abstract
This presentation aims to review advances in mathematical models used in poultry nutrition and production in the past decades and present an overview of the current status. Models have been ...developed to improve understanding of growth, voluntary feed intake, nutrient utilization, body composition, responses to nutrient supply, environmental changes, and stressors. Growth models for broilers, turkeys, ducks, layers, and breeders are available mainly based on the Gompertz curve, but a few other mathematical functions are also used. A few models can simulate egg production in layers and breeders. The EFG and Avinesp models, tools from feed additive and genetic companies, among others, will be described or mentioned. These models can describe genetic differences and estimate energy, amino acids, calcium, and phosphorus requirements or multiple biological responses to specific nutrient levels. Most models use the concept of ideal protein or balanced protein to describe responses to amino acid levels. However, very few models can describe responses to modifications of one or two specific amino acids. Compartmental models are mainly based on main chemical components such as water, body and feather protein, fat, and ash. Poultry models seldom consider variability due to feeding ingredient quality, fiber, fat, other mineral composition, or variation in nutrient digestibility. However, some models can predict responses to exogenous enzymes. Most applications can predict body weights and yields at a specific age, and some can estimate nitrogen, calcium, and phosphorus excretion. These models can be integrated with feed formulation software, economic data, and optimizers to simulate multiple conditions and estimate biological, economic, and environmental optimums. Poultry enterprise models can describe the whole production system, estimate the optimum combination of resources, aid in planning and scheduling, and determine strategies for growth. Currently, no official recommendations from academic or private groups are based only on models to estimate nutrient levels. Combinations of empirical data and model results are frequently used for nutritional decision-making. A few tools are available for specialized personnel to decide the energy and amino acid levels to use. The application of electronics and telecommunications triggered the fast production of enormous volumes of data from diverse poultry production sectors. This big data avalanche is starting to help modelers to integrate more accurate information and incorporate natural variability. However, integration between current models and significant data results is still under development. Despite increasing international collaboration in modeling, poultry model developments keep great independence and fundamental differences. One critical issue needed for faster development of poultry modeling is to increase education in modeling. The lack of academic programs offering modeling classes related to poultry caused the low current application of models. However, awareness about the benefits of modeling has increased in the past few years, and efforts are under development.
Adequate pullet nutrition is essential to reach BW and suitable body composition for reproduction. An experiment was conducted to determine the effects of 4 dietary amino acid (AA) levels on BW, ...flock uniformity, body conformation, organ, leg, and feathering development of broiler breeder pullets during the rearing phase from 5 to 24 wk. A total of 1,360 Cobb-500 slow-feathering (SF) pullets were randomly placed in 16-floor pens with 85 females per pen. Diets with corn, soybean meal, and wheat-midds were formulated without protein restriction maintaining minimum ratios between essential AA and Lys on a digestible (dig) ideal basis. Treatments consisted of 4 dietary AA levels with 80% (low-AA), 90% (moderate-AA), 100% (standard-AA), and 110% (high-AA) of the Cobb-Vantress recommendations guided by dig Lys using balanced protein. Up to 4 wk, all pullets were fed a common starter crumble diet. Grower and developer mash diets were fed to pullets from 5 to 15 wk and from 16 to 24 wk, respectively. Pullets fed standard-AA and high-AA diets were heavier (P < 0.001) than those fed low-AA diets at 10, 15, and 20 wk of age. High-AA diets resulted in better (P = 0.040) flock uniformity at 10 wk. Pullets fed a high-AA diet had the highest (P = 0.041) relative breast weight at 20 wk of age and the lowest (P = 0.044) deposits of abdominal fat at 15 wk of age. Fleshing increased (P < 0.05) as AA content rise in the diet, while the relative shank length (P < 0.001) and the number of wing juvenile feathers (P = 0.004) decreased. Pullets fed the lowest dietary AA level had the longest (P = 0.007) small intestine relative to BW at 10 wk of age, but a smaller (P = 0.001) liver than those fed moderate and standard-AA diets at 20 wk of age. Dietary AA levels have important effects on pullet BW, fleshing, and organ development during rearing with potential reproductive performance impacts.
Drying temperature (DT) of corn can influence its nutritional quality, but whether this is influenced by endosperm hardness is not clear. Two parallel experiments were conducted to investigate the ...effects of 2 yellow dent corn hybrids with average and hard kernel hardness, dried at 3 temperatures (35, 80, and 120°C), and 2 supplementation levels of an exogenous amylase (0, 133 g/ton of feed) on live performance, starch and protein digestibility, and energy utilization of Ross 708 male broilers. Twelve dietary treatments consisting of a 2 × 3 × 2 factorial arrangement were evaluated using 3-way ANOVA in a randomized complete block design. In Experiment 1, a total of 1,920 male-chicks were randomly allocated to 96 floor pens, whereas 480 day-old chicks were distributed among 96 cages for Experiment 2. At 40 d, interaction effects (P < 0.05) were detected on BWG, FCR, and flock uniformity. Supplementation with exogenous amylase resulted in heavier broilers, better FCR and flock uniformity, only in the diets based on corn dried at 35°C. Additionally, interaction effects were observed on FCR due to kernel hardness and DT (P < 0.01), kernel hardness and amylase supplementation (P < 0.001), and DT and amylase supplementation (P < 0.05). Exogenous amylase addition to the diets based on corn with an average hardness improved FCR up to 2 points (1.49 vs. 1.51 g:g) whereas there was no effect of amylase on FCR of broilers fed diets based on corn with hard endosperm. Total tract retention of starch was increased (P < 0.05) in broilers fed diets based on corn with average kernel hardness compared to hard kernel. Corn dried at 80 and 120°C had up to 1.21% points less starch total tract retention than the one dried at 35°C. Supplementing alpha-amylase resulted in beneficial effects for broiler live performance, energy utilization, and starch total tract digestibility results. Treatment effects on starch characteristics were explored. Corn endosperm hardness, DT and exogenous amylase can influence the live performance of broilers. However, these factors are not independent and so must be manipulated strategically to improve broiler performance.
Abstract
Two experiments were conducted to test the hypothesis that corn kernel hardness and drying temperature influence the ileal digestibility of starch and amino acids (AA), as well as apparent ...total tract digestibility (ATTD) of gross energy (GE) and total dietary fiber (TDF) in diets for growing pigs. Two corn varieties with average or hard endosperm were grown and harvested under similar conditions, and after harvest, each variety was divided into 2 batches that were dried at 35 and 120 °C, respectively. Therefore, four batches of corn were used. In experiment 1, 10 pigs (67.00 ± 2.98 kg) with a T-cannula installed in the distal ileum were allotted to a replicated 5 × 5 Latin square design with 5 diets and 5 periods giving 10 replicates per diet. A nitrogen-free diet and four diets containing each source of corn as the only AA source were formulated. Results indicated that neither variety of corn nor drying temperature influenced apparent ileal digestibility of starch in the grain. The standardized ileal digestibility of most AA was less (P < 0.05) in corn dried at 120 °C compared with corn dried at 35 °C resulting in concentrations of most standardized ileal digestible AA being less (P < 0.05) in corn dried at 120 °C than in corn dried at 35 °C. In experiment 2, 40 pigs (20.82 ± 1.74 kg) were housed in metabolism crates and allotted to 4 diets with 10 replicate pigs per diet. The four corn-based diets used in experiment 1 were also used in experiment 2. Feces and urine were collected using the marker-to-marker approach with 5-d adaptation and 4-d collection periods. Results indicated that diets containing hard endosperm corn had greater (P < 0.05) ATTD of TDF than diets containing average endosperm corn. The ATTD of GE in hard endosperm corn was also greater (P < 0.05), and concentrations of digestible energy and metabolizable energy in hard endosperm corn were greater (P < 0.01) than in average endosperm corn. Diets containing corn dried at 120 °C had greater (P < 0.05) ATTD of TDF compared with diets containing corn dried at 35 °C; however, drying temperature did not influence the ATTD of GE. In conclusion, endosperm hardness did not influence the digestibility of AA and starch; however, drying corn at 120 °C reduced digestible AA concentrations. Hard endosperm corn had greater ATTD of GE and TDF, but drying temperature did not influence energy digestibility.
High drying temperature reduces the concentration of digestible amino acids in corn, but does not influence energy digestibility. Endosperm hardness did not influence amino acid digestibility, but hard endosperm corn has greater energy digestibility than average endosperm corn.
Lay Summary
Drying temperatures and corn varieties that inherently differ in kernel hardness, virtuousness, and protein solubility index may influence nutrient digestibility in corn. However, information about interactive effects of corn source (i.e., endosperm hardness) and drying method on nutrient digestibility is limited. Therefore, two experiments were conducted to test the hypothesis that corn source and drying temperature influence energy and nutrient digestibility in corn. Two corn varieties (i.e., average or hard endosperm) were planted in plots with similar soil and similar agronomic conditions and harvested in the same week. Both corn sources were dried at 35 °C or 120 °C. Results indicated that endosperm hardness did not influence the apparent ileal digestibility of starch or standardized ileal digestibility (SID) of amino acids (AA) in pigs; however, values for SID of most AA in corn dried at 120 °C were less than in corn dried at 35 °C. Hard endosperm corn also had greater apparent total tract digestibility of gross energy and total dietary fiber than corn with average endosperm, but drying temperature did not influence energy digestibility. Further research is needed to determine the optimum drying temperature and corn variety to maximize nutritional value in corn.
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