Effects of Feed Restriction and Realimentation on Digestive and Immune Function in the Leghorn Chick

Effects of spray-dried plasma on performance, carcass parameters, tibia quality and Newcastle disease vaccine efficacy in broiler chicken fed corn-soy diets with two varying levels of digestible amino acids and AMEn density

This study aimed to determine the effects of spray dried plasma (SDP) on growth performance, carcass traits, tibia quality, and hemagglutination inhibition titers in broilers fed two nutritional strategies with high or low nutrient density. In the study, 816 one-day-old Ross 308 male broiler chickens were divided into a 2 × 2 factorial arrangements consisting of four treatment groups with 12 replicates (17 birds/replicate) based on diets with high nutrient density (HND) or low nutrient density (LND) from d 0 to 42 and receiving either control or 1% SDP diets during d 0 to 10. The results showed that feed intake (FI) and body weight gain (BWG) were increased (P < 0.05) and feed conversion ratio (FCR) was significantly reduced (P = 0.003) for broilers fed HND diets from d 0 to 42. The inclusion of SDP increased the BWG (P < 0.001), FI (P < 0.001), and FCR (P < 0.05) during d 0 to 10 of broiler life but not effect of SDP was observed for the whole 0-42 d period. Carcass yield increased with HND (P < 0.001) and dietary SDP (P = 0.002). However, HND feeding significantly decreased liver (P < 0.001), bursa of Fabricius (P = 0.002), abdominal fat (P < 0.001), proventriculus (P < 0.001) and gizzard weight (P < 0.001), but increased heart weight (P = 0.013), although spleen weight remained unaffected (P > 0.05) on d 42. Tibial bone morphometric and mechanical properties improved (P < 0.05) with SDP supplementation, and bone ash, Ca, and P remained unaffected (P > 0.05) on d 14. With the exception at d 28 (P = 0.037), the antibody titer to ND virus was similar among all treatment groups (P > 0.05) at d 0, 14, and 42. In conclusion, HND diets improve performance of broilers during the whole period and SDP supplementation during starter phase improve performance at this period, but also increased carcass yield, and tibial quality. Therefore, inclusion of SDP in the starter diet could be a beneficial nutritional strategy to improve the health and production of broilers provided feeding strategies using various nutrient densities.

Genotype-environment interaction in layer chickens in the growing stage: comparison of three genotypes at two different feeding levels with or without red mite (Dermanyssus gallinae) infestation

This study investigated how early growth was affected in various chicken genotypes, which were fed ad libitum or restricted and with or without poultry red mite (PRM) infestation. Atak-S (AS), New Hampshire Red (NHR), and Light Sussex (LS) genotypes were used in the study. In total, 120 chicks were used from each genotype. Four groups were formed: feed-restricted (FR) and infested with parasite (P + ), FR only, fed ad libitum and P + , and fed ad libitum only. Feed restriction was applied as 20 % of the feed consumption of the group fed ad libitum the day before for each genotype. The study was conducted between 2 to 12 weeks of age. Weekly live weights and feed consumption were recorded, and the feed conversion ratio was calculated. Traps were placed in cages to count parasites. Regarding the live weight, NHR tolerated the PRM infestation in the ad libitum feed conditions better than other genotypes. While the infested NHR and AS birds had lower live weights than the non-infested ones under FR conditions, there was no difference between infested and non-infested birds of NHR and AS genotypes when they fed ad libitum. The feed consumption of infested AS and NHR birds was higher than that of non-infested counterparts when fed ad libitum. By contrast, the LS chicks consumed less food in the infested environment. In conclusion, the genotypes responded differently to PRM infestation in different feeding environments.

The Effect of Feeding Restriction on the Microbiota and Metabolome Response in Late-Phase Laying Hens

Simple Summary

Feeding restriction (FR) is essential to reduce excessive fat deposits caused by overfeeding in hens and to ensure their reasonable nutritional requirements for egg production. Effective FR is particularly crucial for raising hens in the late phase of laying; because hens require lower energy at this stage, overfeeding reduces their feed efficiency and increase feed costs. The gut microbiota is involved in various metabolic pathways of laying hens, including in late-phase age. Thus, changes in feeding interventions can alter the presence of gut microorganisms and the structure of the microbial community, resulting in altered metabolic regulation. In this study, we investigate the microbiota and metabolome responses of late-phase laying hens under FR. Our results provide data to access the profile of the cecal bacteria community, their relevance to cecal and serum metabolites, and their FR biosynthetic pathways related to host nutritional requirements and intestinal nutrient availability. Moreover, understanding the principles of host-microbial interaction is essential for developing cost-effective strategies to improve laying hens’ production.

Abstract

This study investigated cecal bacterial community profile, cecal and serum metabolites, and its biosynthesis pathway in late-phase laying hens during 6 weeks feeding restriction (FR), using 16S rDNA as gene sequencing and non-targeted LC-MS/MS as metabolomics approach. We used three groups (ad libitum, FR20, and FR40). FR can reduce excessive fat in late-phase laying hens, while egg production rate is not affected, except for the FR40 group. In phylum level, FR20 had more population of Bacteriodetes and Firmicutes amongst groups. The same result is at genus level, FR20 were higher of the predominant genus (Bacteroides and Rikenellaceae_RC9_gut_group). Both of FR20 and FR40 reduced Proteobacteria as potential pathogenic bacteria. Non-targeted metabolomic analysis revealed that FR20 modified 20 metabolites in cecal and 10 metabolites in serum of laying hens, whereas 48 cecal metabolites and 31 serum metabolites has revealed in FR40. KEGG assay showed FR20 and FR40 upregulated lipid, carbohydrate, amino acid, nucleic acid pathway, and FR40 modified steroid metabolism in cecal analysis. In serum, only FR40 modified lipid, amino acid pathway, and carbohydrate biosynthesis were shown. This study showed that FR during late-phase laying hens altered the microbiome composition, modified metabolites profile and biosynthesis of the cecal as well as serum.

Hematology and Blood Chemistry Reference Values of Captive Adult Black-Faced Ibis (Theristicus melanopis melanopis)

Hematology and blood chemistry reference values in wildlife animals are considered a key element to evaluate their health and welfare status. The incidence of birds rescued is increasing, thus, rehabilitation centers worldwide need valid reference values to improve medical care for wild individuals. The objective of this study was to obtain the reference values of the adult black-faced ibis (Theristicus melanopis). Blood was taken from adult rehabilitated birds and analyzed to obtain red and white line values such as hematocrit, hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), heterophils, lymphocytes, monocytes, eosinophils and basophils. Values for blood glucose, proteins, albumin, globulin, calcium, phosphorus, blood urea nitrogen (BUN), creatinine, alkaline phosphatase, aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), creatine phosphokinase (CPK) and albumin:globulin (A/G) ratio were also obtained. The results were similar to others reported for species of the Threskiornithidae family (bald, glossy and Puna ibises), but showed higher values for white blood cells (WBC), heterophils, monocytes and heterophil-lymphocyte (H/L) ratio, but lower values for basophils and eosinophils. Moreover, higher values in albumin, BUN and CPK were observed. This is the first report of the hematology references values for the black-faced ibis showing differences to other closely related species. The results may be of use in rescue and rehabilitation centers for animal welfare and health assessments of the black-faced ibis.

A feed restriction milieu for Pekin meat ducks that may improve gait characteristics but also affects gut leakiness

In a previous study, we demonstrated that a 15% feed restriction (FR) during the first 2 wk after hatch could improve gait in Pekin meat ducks, but did result in reduced breast mass. We hypothesized that feed restriction after day 5 following muscle satellite cell development would allow the full growth of the breast meat. To accomplish this goal, 300 1-day-old ducklings (Maple Leaf Farms Inc.) were randomly allocated to 1 of the 3 groups (n = 4 pens, 25 ducks per pen): (1) Control group fed to ad libitum; (2) 85% daily feed intake from days 1 to 14 (FR 85% 1-14); 85% daily feed intake from days 5 to 14 (FR 85% 5-14). All ducks were vaccinated with inactivated Salmonella enteritidis on day 14 and boosted on day 26. The FR 85% 5-14 did show similar production standards to controls, and improved gait characteristics (P < 0.05). To determine if the partial feed restriction would have an impact on intestinal epithelial tight junction integrity, we treated ducks on days 7, 14, 21, 28, and 35 with 8.32 mg/kg FITC-d in water per os and blood samples were obtained via the tibial vein 1 h later. Serum samples were analyzed for presence and quantification of FITC-d. Feed restriction elicited a significant increase in FITC-d permeability at all points of evaluation. Anti-S. enteritidis specific IgY responses were assessed by ELISA from serum collected at 14 D, 28 D, and 35 D. Although all ducks showed an increase humoral immune response to the S. enteritidis, both feed restricted groups showed reduced IgY production compared to ad lib controls. Our data suggest that although the FR 5-14 feed restriction paradigm may reduce gait abnormalities without affecting production rates, some challenges exist due to increased gut leakiness or decreased acquired immune activity. Future studies will look at altering the feed restriction milieu to ameliorate these challenges.

Effect of early feed restriction programs and genetic strain on humoral immune response production in broiler chickens

Two experiments were conducted to compare the immunocompetence of Cobb high performance and rustic Label Rouge broilers and the influence of reduced growth rates subsequent to feed restriction on the IgY anti-bovine serum albumin (BSA) response. In the first experiment (EXP), 360 broilers were assigned to 36 cages from 1 to 42 days of age. A completely randomized design was applied in a 3 × 2 factorial arrangement, with 3 groups (Label Rouge, Cobb ad libitum, and Cobb Restricted Intake), and 2 levels of energy (3,100 and 2,800 kcal/kg); there were 6 replicates per treatment. In the second EXP, 384 Cobb 500 male broilers were randomly assigned to the following feed restriction programs from day 8 to 16: Control, fed ad libitum; Quantitative (80% of the control amount); By Time (fed for 8 h/d), and Qualitative (80% limiting nutrients) restriction. Blood samples were collected on days 35 and 42 (EXP 1) and weekly from day 7 to 42 (EXP 2) for IgY anti-BSA quantification. In EXP 1, the production of IgY anti-BSA was lower in the Cobb groups (P < 0.0001) than in the Label Rouge group, and higher in the Cobb Restricted Intake group (P < 0.0001) compared with the same genetic strain fed ad libitum. Birds fed the low energy diet presented lower (P ≤ 0.06) IgY anti-BSA, independent of genetics. In EXP 2, no difference (P > 0.05) was observed 1 wk after the first BSA inoculation. However, at day 28, birds in all feed restriction programs had higher (P < 0.05) IgY anti-BSA than the Control group fed ad libitum. At day 35, the greatest residual effect of IgY anti-BSA was observed in the Quantitative restriction group. No differences (P > 0.05) were observed between groups after 42 d. The 3 early feed restriction programs had beneficial effects on the humoral immune response. Overall, Quantitative restriction promoted a longer lasting IgY anti-BSA response. Lower growth rate, due to feed restriction or genetic potential, improves humoral immunity in broiler chickens.

Large muscles are beneficial but not required for improving thermogenic capacity in small birds

It is generally assumed that small birds improve their shivering heat production capacity by developing the size of their pectoralis muscles. However, some studies have reported an enhancement of thermogenic capacity in the absence of muscle mass variation between seasons or thermal treatments. We tested the hypothesis that an increase in muscle mass is not a prerequisite for improving avian thermogenic capacity. We measured basal (BMR) and summit (M_sum) metabolic rates of black capped chickadees (Poecile atricapillus) acclimated to thermoneutral (27 °C) and cold (-10 °C) temperatures and obtained body composition data from dissections. Cold acclimated birds consumed 44% more food, and had 5% and 20% higher BMR and M_sum, respectively, compared to individuals kept at thermoneutrality. However, lean dry pectoralis and total muscle mass did not differ between treatments, confirming that the improvement of thermogenic capacity did not require an increase in skeletal muscle mass. Nevertheless, within temperature treatments, M_sum was positively correlated with the mass of all measured muscles, including the pectoralis. Therefore, for a given acclimation temperature individuals with large muscles do benefit from muscle size in term of heat production but improving thermogenic capacity during cold acclimation likely requires an upregulation of cell functions.

High costs of infection: Alphavirus infection reduces digestive function and bone and feather growth in nestling house sparrows (Passer domesticus)

Increasingly, ecoimmunology studies aim to use relevant pathogen exposure to examine the impacts of infection on physiological processes in wild animals. Alphaviruses are arthropod-borne, single-stranded RNA (ssRNA) viruses ("arboviruses") responsible for millions of cases of human illnesses each year. Buggy Creek virus (BCRV) is a unique alphavirus that is transmitted by a cimicid insect, the swallow bug, and is amplified in two avian species: the house sparrow (Passer domesticus) and the cliff swallow (Petrochelidon pyrrhonota). BCRV, like many alphaviruses, exhibits age-dependent susceptibility where the young are most susceptible to developing disease and exhibit a high mortality rate. However, alphavirus disease etiology in nestling birds is unknown. In this study, we infected nestling house sparrows with Buggy Creek virus and measured virological, pathological, growth, and digestive parameters following infection. Buggy Creek virus caused severe encephalitis in all infected nestlings, and the peak viral concentration in brain tissue was over 34 times greater than any other tissue. Growth, tissue development, and digestive function were all significantly impaired during BCRV infection. However, based on histopathological analysis performed, this impairment does not appear to be the result of direct tissue damage by the virus, but likely caused by encephalitis and neuronal invasion and impairment of the central nervous system. This is the first study to examine the course of alphavirus diseases in nestling birds and these results will improve our understanding of age-dependent infections of alphaviruses in vertebrate hosts.

Small intestinal hydrolysis of plant glucosides: higher glucohydrolase activities in rodents than passerine birds

Glycosides are a major group of plant secondary compounds characterized by one or more sugars conjugated to a lipophilic, possibly toxic aglycone, which is released upon hydrolysis. We compared small intestinal homogenate hydrolysis activity of three rodent and two avian species against four substrates: amygdalin and sinigrin, two plant-derived glucosides, the sugar lactose, whose hydrolysis models some activity against flavonoid and isoflavonoid glucosides, and the disaccharide sugar maltose (from starch), used as a comparator. Three new findings extend our understanding of physiological processing of plant glucosides: (1) the capacity of passerine birds to hydrolyze plant glucosides seems relatively low, compared with rodents; (2) in this first test of vertebrates' enzymic capacity to hydrolyze glucosinolates, sinigrin hydrolytic capacity seems low; (3) in laboratory mice, hydrolytic activity against lactose resides on the enterocytes' apical membrane facing the intestinal lumen, but activity against amygdalin seems to reside inside enterocytes.

Growth and development of house sparrows (Passer domesticus) in response to chronic food restriction throughout the nestling period

Birds have evolved phenotypic plasticity in growth and developmental patterns in order to respond to fluctuating environmental conditions and to mitigate the impact of poor feeding on fitness. Chronic food shortage can occur during chick development in the wild, and the responses of altricial birds have not been thoroughly studied. House sparrow (Passer domesticus) nestlings were raised in the laboratory on age-specific meal sizes (controls) or meal sizes 25% less than age-specific amounts (food-restricted) and analyzed at 6, 9 and 12 days post-hatch for differences in growth and development. Food-restricted birds had significantly reduced body mass and body temperature, but skeletal growth was maintained with respect to controls. Muscle mass was significantly reduced and muscle water content was slightly, though not significantly, higher in food-restricted birds, which may reflect slight developmental immaturity. Assimilation organ masses, summed enzymatic capacity of the intestine and lipid content of the liver were significantly reduced in food-restricted birds. Findings from this study indicate that altricial birds experiencing chronic, moderate food restriction throughout the nestling period may allocate resources to structural growth through energy-saving reductions in mass of assimilation organs and body temperature.

One Alpha-hydroxycholecalciferol Improves Growth Performance, Tibia Quality, and Meat Color of Broilers Fed Calcium- and Phosphorus-Deficient Diets

An experiment was conducted to evaluate the effects of one alpha-hydroxycholecalciferol (1α-OH D₃) on growth performance, tibia quality, and skin and meat color in broilers fed calcium (Ca)- and phosphorus (P)-deficient corn-soybean meal diets. A total of 288 male Ross broilers, at 21 days of age, were randomly assigned to three treatments with eight cages per treatment. Three levels of 1α-OH D₃ (0, 5, and 10 μg/kg) were added to a basal diet (0.50% Ca, 0.13% non-phytate phosphorus (NPP), and 0.35% total phosphorus (tP)) without vitamin D₃. As a result of this study, the addition of 1α-OH D₃ increased body weight gain (p<0.001), feed intake (p = 0.007), feed efficiency (p<0.001), tibia weight (p = 0.002), length (p<0.001), breaking-strength (p = 0.012), ash (p<0.001), Ca (p<0.001), and P content (p = 0.004). Dietary 1α-OH D₃ enhanced breast meat yellowness (p = 0.015) and the length and weight of the small intestine of the broilers. Moreover, 1α-OH D₃ decreased serum Ca concentration (p = 0.074) and breast meat redness (p = 0.010). These results indicate that the 1α-OH D₃ improves growth, tibia quality, and meat color in broilers fed Ca- and P-deficient corn-soybean meal diets.

Effect of malnutrition on iron homeostasis in black-necked swans (Cygnus melanocoryphus)

The Cayumapu River black-necked swan (Cygnus melanocoryphus) population in southern Chile suffered a syndrome of malnutrition and hyperferremia in 2005. The iron metabolic imbalance could not be explained on the basis of the quality of their diet. Hence, the primary objective of this study was to determine the relationship between malnutrition and iron homeostasis in black-necked swans. It was proposed that catabolic processes could increase serum iron levels due to the release of endogenous iron from tissues. A free-living swan population undergoing natural nutritional imbalance due to molting was studied. In addition, swans captured were subjected to a diet restriction until they became emaciated. The results revealed that neither lipolytic activity nor emaciation affected serum iron concentrations. The increment of total iron binding capacity observed was in agreement with the reduction of endogenous iron stored, with the increase of erythropoeitic demand, or with both. Future studies are needed to determine the effect of incremental erythropoietic activity on iron homeostasis in anemic, malnourished birds.

Developmental adjustments of house sparrow (Passer domesticus)nestlings to diet composition

House sparrow nestlings are fed primarily on insects during the first 3 days of their life, and seeds become gradually more important afterwards. We tested whether developmental changes in size and functional capacity of the digestive tract in young house sparrows are genetically hard-wired and independent of diet, or can be modified by food type. Under laboratory conditions, we hand-fed young house sparrows with either a starch-free insect-like diet, based mainly on protein and fat, or a starch-containing diet with a mix of substrates similar to that offered to older nestlings in natural nests when they are gradually weaned from an insect to a seed diet. Patterns of overall development in body size and thermoregulatory ability, and in alimentary organ size increase, were relatively similar in house sparrow nestlings developing on both diets. However, total intestinal maltase activity, important in carbohydrate breakdown, was at least twice as high in house sparrow nestlings fed the starch-containing diet (P&lt;0.001). The change in maltase activity of nestlings was specific, as no change occurred in aminopeptidase-N activity in the same tissues. There was no significant diet effect on digesta retention time, but assimilation efficiency for radiolabeled starch tended to be higher (P=0.054) in nestlings raised on starch-containing diet. Future studies must test whether the diet-dependent increase in maltase activity during development is irreversible or reversible, reflecting, respectively, a developmental plasticity or a phenotypic flexibility.

Dietary protein quality and feed restriction influence abundance of nutrient transporter mRNA in the small intestine of broiler chicks

The objective of this study was to evaluate the effect of dietary protein quality on intestinal peptide transporter (PepT1), amino acid transporter [Na+-independent cationic and zwitterionic amino acid transporter (b(o,+)AT), excitatory amino acid transporter 3 (EAAT3), Na+-independent cationic and Na+-dependent neutral amino acid transporter (y+ LAT2), and Na+-independent cationic amino acid transporter 2 (CAT2)], glucose transporter [Na+-dependent glucose and galactose transporter 1 (SGLT1) and Na+-independent glucose, galactose, and fructose transporter 2 (GLUT2)], and digestive enzyme [aminopeptidase N (APN)] mRNA abundance in 2 lines of broilers (A and B). At day of hatch (doh), chicks from both lines were randomly assigned to corn-based diets containing 24% crude protein with either soybean meal (SBM) or corn gluten meal (CGM) as the supplemental protein source. Chicks were given unlimited access to feed and water. Groups of chicks from both lines were also assigned to the SBM diet at a quantity restricted to that consumed by the CGM group (SBM-RT). Intestinal transporter and enzyme mRNA abundance was assayed by real-time PCR using the absolute quantification method. Abundance of PepT1, EAAT3, and GLUT2 mRNA was greater in Line B (P < 0.03), whereas APN and SGLT1 were greater in Line A (P < 0.04). When feed intake was equal (CGM vs. restricted SBM), a greater abundance of PepT1 and b(o,+)AT mRNA was associated with the higher quality SBM (P < 0.04), whereas a greater abundance of EAAT3 and GLUT2 mRNA was associated with the lower quality CGM (P < 0.01). When feed intake was restricted (SBM vs. SBM-RT), a greater abundance of PepT1 mRNA was associated with the restricted intake (P < 0.04). These data demonstrate that both dietary protein quality and feed restriction influence expression of nutrient transporter mRNA in the small intestine of broiler chicks.