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There is a trend towards extended periods of lay in the laying hen industry. Extended cycles without a moulting stage gives the opportunity to obtain more eggs from a single hen. However, appropriate management and care for older laying hens is needed. In this trial we assessed the prevalence of conditions in old laying hens with a focus on neoplastic diseases. In total 150 ISA Brown and 150 Dekalb white laying hens were selected at 86 weeks of age. Of each hen line, 75 hens were necropsied at 86 weeks of age; the other half were monitored for 44 weeks after which they were necropsied. At week 86, 15.3% of the hens suffered from a neoplasm, ISA Brown being the most affected. During the follow up period, 50 birds died because of a natural cause of which 20 hens showed signs of a neoplasms. At the end of the follow up period, 43% of the hens were affected by a neoplasm. Adenocarcinoma was the most prevalent neoplasm and equally distributed among both hen lines. Leiomyomas were most frequently observed in ISA brown hens. Among causes of death, 19.05% of ISA brown and 20.69% of Dekalb White was attributed to a neoplasm. Furthermore, link with ovarian activity and other pathologies were made with significant correlations between adenocarcinomas and inactive ovaries. In conclusion, this study shows that the prevalence of adenocarcinoma and leiomyoma is a factor to be considered in longer laying cycles with 1/5th of the mortality caused by these processes.RESEARCH HIGHLIGHTSAt 86 weeks of age, the prevalence of neoplasms was 15.3%, mainly in brown hens.At 130 weeks of age, 43% of the hens were affected by a neoplasm.Adenocarcinoma was the most prevalent neoplasm equally distributed among hen lines.Leiomyoma was the second most prevalent neoplasm, mainly found in brown hens.
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Adenocarcinoma , Leiomioma , Animais , Feminino , Galinhas , Prevalência , Óvulo , Adenocarcinoma/veterinária , Leiomioma/veterináriaRESUMO
The objective of this study was to evaluate the interaction of zinc source (ZnSO4 vs. zinc amino acid complex) and vitamin E level (50 IU vs. 100 IU) on performance and intestinal health of broilers exposed to a temperature challenge in the finisher period. A total of 1224 day old male Ross 308 broilers were randomly distributed among 4 dietary treatments (9 replicates per treatment). Dietary treatments were organized in a 2 × 2 factorial arrangement: two sources of zinc, 60 mg/kg of Zn as ZnSO4 .7H2 O or 60 mg/kg of Zn as zinc amino acid complexes (ZnAA) combined with two levels of vitamin E (50 or 100 IU/kg). Zinc and vitamin E were added to a wheat/rye-based diet that was designed to create a mild nutritional challenge. From day 28 until day 36 (finisher period), all birds were subjected to chronic cyclic high temperatures (32°C ± 2°C and RH 55-65% for 6 h daily). The combination of ZnAA and 50 IU/kg of vitamin E improved weight gain in the starter (day 0-10), finisher (day 28-36) and overall period (day 0-36) and feed conversion ratio in the starter (day 0-10) and finisher phase (day 28-36). Providing Zn as ZnAA significantly improved villus length and villus/crypt ratio in the starter, grower and finisher period and decreased infiltration of T-lymphocytes and ovotransferrin leakage in the finisher period. In conclusion, providing broilers with a diet supplemented with ZnAA and a vitamin E level of 50 IU/kg, resulted in better growth performance as compared to all other dietary treatments. Interestingly, under the conditions of this study, positive effects of ZnAA on performance did not occur when vitamin E was supplemented at 100 IU/kg in feed. Moreover, providing zinc as zinc amino acid complex improved intestinal health.
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Ração Animal , Galinhas , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Masculino , Temperatura , Vitamina E/farmacologia , ZincoRESUMO
The aim of the present study was to evaluate the transfer of maternal dietary fatty acids (FA) from the yolk to the developing offspring, with special emphasis on n-3 FA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Six hundred forty Ross 308 breeders were housed from 6 to 58 wk of age in 16 pens resulting in 4 replicates per dietary treatment. They were fed 1 of 4 diets: a basal diet, rich in n-6 FA (CON), or an n-3 FA enriched diet formulated to obtain an EPA/DHA ratio of 1/1 (EPA=DHA), 1/2 (DHA), or 2/1 (EPA). At 28, 43, and 58 wk of age, 20 eggs per treatment were collected and analyzed for FA composition. At these same breeder ages, 600 fertilized eggs per treatment were incubated. At hatch the residual yolks of 25 chicks per treatment were collected and analyzed for FA composition. At every hatch, 180 chicks per treatment were raised under standard conditions and livers were sampled at d 1, 14, 28, and 38 d for FA analysis. Concentrations of EPA in the yolk and residual yolk of eggs laid by EPA-fed breeders were highest, next-to-highest for EPA=DHA-fed breeders, next-to-lowest for DHA-fed breeders, and lowest in those laid by control hens, reflecting the inclusion levels in the maternal diets. Yolk and residual yolk DHA concentrations, however, were not only elevated due to DHA supplementation, compared with the control diet, but also due to EPA supplementation. Offspring hepatic EPA concentrations were elevated until d 28 in all n-3 enriched groups, whereas hepatic DHA concentrations were only affected by EPA=DHA and DHA supplementation at d 1. No differences were found in hepatic DHA concentrations at later offspring ages. Considering the role of EPA and DHA in early development and growth, the maternal supply of these n-3 FA might improve offspring health and performance.
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Galinhas/fisiologia , Ácidos Docosa-Hexaenoicos/metabolismo , Ácido Eicosapentaenoico/metabolismo , Reprodução/efeitos dos fármacos , Saco Vitelino/efeitos dos fármacos , Fatores Etários , Ração Animal/análise , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Ácidos Docosa-Hexaenoicos/administração & dosagem , Relação Dose-Resposta a Droga , Ácido Eicosapentaenoico/administração & dosagem , Ácidos Graxos/administração & dosagem , Ácidos Graxos/metabolismo , Feminino , Masculino , Óvulo/efeitos dos fármacos , Óvulo/fisiologia , Distribuição Aleatória , Saco Vitelino/metabolismoRESUMO
Feather pecking and high mortality levels are significant welfare problems in non-cage housing systems for laying hens. The aim of this study was to identify husbandry-related risk factors for feather damage, mortality, and egg laying performance in laying hens housed in the multi-tier non-cage housing systems known as aviaries. Factors tested included type of system flooring, degree of red mite infestation, and access to free-range areas. Information on housing characteristics, management, and performance in Belgian aviaries (N=47 flocks) were obtained from a questionnaire, farm records, and farm visits. Plumage condition and pecking wounds were scored in 50 randomly selected 60-week-old hens per flock. Associations between plumage condition, wounds, performance, mortality, and possible risk factors were investigated using a linear model with a stepwise model selection procedure. Many flocks exhibited a poor plumage condition and a high prevalence of wounds, with considerable variation between flocks. Better plumage condition was found in wire mesh aviaries (P<0.001), in aviaries with no red mite infestation (P=0.004), and in free-range systems (P=0.011) compared to plastic slatted aviaries, in houses with red mite infestations, and those without a free-range area. Furthermore, hens in aviaries with wire mesh flooring had fewer wounds on the back (P=0.006) and vent (P=0.009), reduced mortality (P=0.003), and a better laying performance (P=0.013) as compared to hens in aviaries with plastic slatted flooring. Flocks with better feather cover had lower levels of mortality (P<0.001). Red mite infestations were more common in plastic slatted aviaries (P=0.043). Other risk factors associated with plumage condition were genotype, number of diet changes, and the presence of nest perches. Wire mesh flooring in particular seems to have several health, welfare, and performance benefits in comparison to plastic slats, possibly related to decreased feather pecking, better hygiene, and fewer red mite infestations. This suggests that adjustments to the aviary housing design may further improve laying hen welfare and performance.
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Bem-Estar do Animal , Galinhas , Abrigo para Animais/normas , Doenças das Aves Domésticas/epidemiologia , Animais , Bélgica/epidemiologia , Plumas/patologia , Feminino , Doenças das Aves Domésticas/etiologia , Doenças das Aves Domésticas/mortalidade , Reprodução/fisiologia , Fatores de RiscoRESUMO
Climate change is increasingly manifesting in temperate regions. Laying hens are highly sensitive to heat stress and mitigation strategies should be implemented to reduce the negative effects. The goal of this experiment was to evaluate the effects of betaine in drinking water (0.55 g/L) and 4 h feed restriction during peak heat stress on laying performance, egg quality, blood gas parameters, body temperature (Tb), and oxidative stress in 2 different breeds of laying hens. Therefore, 448 ISA Brown hens (25 wk) and 448 Lohmann LSL classic laying hens (26 wk) were housed in 128 cages (7 hens/cage). Thermoneutral (TN) data was collected for 21 d before cyclic heat stress (HS) (21d; 32 ± 2°C; 6 h daily). During HS, hens were divided into 4 treatments: 1) feed restriction (FR), 2) betaine supplementation in drinking water (BET), 3) feed restriction and betaine supplementation in drinking water (FR-BET), or 4) control (CON). The effects were evaluated after 1 wk of HS (acute heat stress; AHS) and 3 wk of HS (chronic heat stress; CHS). Laying rate and egg mass (EM) diminished during CHS but decreased more in white than brown hens (2.78% and 1.94%; -1.57% and -0.81%, respectively; P = 0.004) and remained unaltered by BET or FR. During AHS, average daily feed intake (ADFI) increased compared to TN, but the increase was higher in white than brown hens (6.36% and 2.62%, respectively; P = 0.001). Egg shell quality deteriorated during AHS and CHS, but was most affected in white hens, FR or BET did not impact this. Blood pCO2, HCO3- and base excess significantly decreased during AHS and CHS, but pH and iCa were unaltered. Blood glucose increased in white hens during AHS compared to TN (P < 0.001), while plasma malondialdehyde increased in brown hens (P < 0.001). Results indicated that laying hens experienced HS, but breed differences were observed and white hens were generally most affected. FR affected feed conversion ratio negatively during CHS. However, FR and BET could not improve laying performance, egg quality, Tb, or blood parameters during HS.
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Microalgae have potentially beneficial effects on animal health and nutritional value when added to feed. Crucial hereby is that intracellular bio-active molecules are released in the intestinal tract. Digestibility of Chlorella vulgaris and its impact on total digestibility of broiler feed is a first step in assessing its characteristics as feed supplement. Different methods could be used to increase the digestibility of the algae. Among other, pulsed electric field (PEF) and freezing to disrupt autotrophic (A) and heterotrophic (H) Chlorella vulgaris cells was assessed to increase their availability followed by in-vivo trials. In these trials effect of algae type (A and H) and effect of PEF-processing was evaluated on the apparent nutrient digestibility. Pulsed electric field showed to have a disruption efficiency of 83.90% and 79.20% for heterotrophic and autotrophic C. vulgaris respectively. Freezing C. vulgaris only showed efficiencies ranging from 3.86 to 11.58%. In the in-vivo trials, microscopic counting of intact C. vulgaris cells showed an increase in digested intact C. vulgaris cells of PEF-processed C. vulgaris compared to nonprocessed cells ranging from 12.16% to 15.20%. Autotrophic C. vulgaris had a higher digestibility compared to heterotrophic C. vulgaris, with an increase of 7.29, 9.44, and 17.29% in digestibility of C. vulgaris in the 1, 2, and 5% feed respectively. Feeds with PEF-processed C. vulgaris showed no significant increase in digestibility compared to nonprocessed C. vulgaris supplemented feeds. The 5% C. vulgaris feeds showed lower fat digestibility than the 1 and 2% and control feeds. Protein digestibility was lower for all C. vulgaris feeds compared to the control feed. There was a significant linear decreasing effect (P < 0.001) for all digestibility parameters. Except for crude ash digestibility, which first lowered for the 1 and 2% feeds, but then increased at 5% inclusion. Considering this study, including low dosages of 1 and 2% of C. vulgaris in broiler feed does not compromise its digestibility.
Assuntos
Ração Animal , Galinhas , Chlorella vulgaris , Dieta , Digestão , Chlorella vulgaris/metabolismo , Animais , Galinhas/fisiologia , Ração Animal/análise , Digestão/fisiologia , Dieta/veterinária , Fenômenos Fisiológicos da Nutrição Animal , Suplementos Nutricionais/análise , Microalgas/química , Eletricidade , Manipulação de Alimentos/métodos , MasculinoRESUMO
In most rabbit farms, breeding does kindle and nurse their kits in single-litter cages throughout their entire reproduction cycle. However, the protective behavior can lead to aggressive displays and injuries when the does are housed in groups. This study aimed to evaluate cage enrichment for reducing the agonistic behavior in part-time group-housed does. A total of eighty does with their 22-day-old kits were allocated to 20 multi-litter cages, with each cage housing four does and their litters for 10 days. Each multi-litter group was subjected to one of four treatments: alfalfa blocks as distraction material (A), wooden panels underneath the platforms (P), both alfalfa and wooden panels (AP), or no extra enrichment (controls, C). This experiment was replicated for three consecutive reproduction cycles. The skin injuries of the does and the kits were scored with a tagged visual analog scale before grouping and at one, three, six, eight, and 10 days after grouping. Computer vision techniques were used to continuously monitor rabbit activity and agonistic behavior (aggression and fleeing/chasing) during the first 24 h after grouping, specifically during light hours. During the first day in the group, 67.2% of the does and 13.4% of the kits acquired new injuries. This increased to 82.0 and 33.2%, respectively after 10 days in the group relative to the onset of grouping. The injury scores of the does increased toward the sixth day after grouping compared to the first (p < 0.001) and were highest on the tenth day for the kits (p < 0.001). On all the observation days, the number of injured does was higher in C compared to A (p = 0.04) and AP treatment (p = 0.005). There were no other treatment effects observed on the doe or kit skin injuries. Rabbit activity was highest after grouping but decreased after the first and second days (p < 0.001). The agonistic interactions between the does involved more fleeing/chasing behavior (62.0%) rather than aggression (38.0%). Although hierarchy fights are likely when unacquainted does are group-housed, the many animals that sustained injuries and the high injury scores confirm that part-time group housing for does is challenging and possibly inevitable. This study has shown that alfalfa, with or without wooden panels, can slightly reduce the number of injured does.
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Studies on the bioavailability, serum levels, and absorption of hydrolyzable tannin compounds are lacking. In this study, we performed a pharmacokinetic trial, measured the serum levels of compounds in broilers that were reared with different feed added or not with tannins, and tested the digestibility of tannins throughout the intestinal tract. Only gallic acid and 4-O-methyl gallic acid were found in the serum. Moreover, gallic acid showed a 41.8% absolute oral bioavailability and a 72.3% relative bioavailability of gallic acid from chestnut extract compared to the standard. The rapid metabolization caused alternating serum levels during the day and night. These patterns were not affected by the feed type or the previous addition of tannins in the feed. The absorption and metabolization in the intestines occurred gradually throughout the intestinal tract. The latter was true for gallic acid as well as ellagic acid, which was not found in the serum. We can conclude that components from chestnut tannins are absorbed throughout all components of the intestinal tract and are eliminated quickly with little interaction from the feed and previous addition of tannins. Moreover, ellagic acid seems to be absorbed but would remain accumulated in the intestinal tissue or be metabolized by the microbiome.
Assuntos
Ácido Gálico , Taninos , Animais , Ácido Elágico , Galinhas , Madeira , DietaRESUMO
This study explores upright versus inverted catching and crating of spent laying hens. Both catching methods were compared using a cost-benefit analysis that focused on animal welfare, ergonomic, and financial considerations. Data were collected on seven commercial farms (one floor system and six aviary systems) during depopulation of approximately 3,000 hens per method per flock. Parameters such as wing flapping frequency, catcher bird interaction, incidence of catching damage and hens dead on arrival (DOA) were measured and compared between catching methods. Ergonomic evaluations were performed via catcher surveys and expert assessment of video recordings. The wing flapping frequency was lower (3.1 ± 0.6 vs. 4.0 ± 0.5, P < 0.001) and handling was gentler (1.9 ± 0.5 vs. 4.4 ± 0.5, P < 0.001), both on a 7-point Likert scale, for upright versus inverted catching. However, more person-hours per 1000 hens were required for upright than inverted catching (8.2 ± 3.2 h vs. 4.8 ± 2.0 h, P = 0.011), with only wing bruises being significantly less common for upright than inverted catching (1.1 ± 0.6 % vs. 1.7 ± 0.7%, P = 0.04). Upright catching was 1.8 times more expensive than inverted catching; compensation for this cost would require a premium price of approximately 0.0005 extra per egg. Ergonomically, both catching methods were considered demanding, although catchers (n = 29) preferred inverted catching. In conclusion, this study showed animal welfare benefits of upright vs. inverted catching. Industry adoption of upright catching will depend on compensation of the additional labor costs, adjustments to labor conditions and shorter loading times.
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Necrotic enteritis, caused by netB toxin-producing Clostridium perfringens type A, is an important disease in broiler chickens worldwide. Earlier attempts to prevent necrotic enteritis by vaccination have not sufficiently taken into account the practical limitations of broiler vaccination. In most published studies on vaccination against necrotic enteritis, multiple doses at different ages are administered, which is not practical for broilers. The aim of this study was to compare the efficacy of subcutaneous single vaccination at day 1 or day 3 and double vaccination at day 3 and day 12, using crude supernatant containing active toxin or formaldehyde-inactivated supernatant (toxoid) of a netB-positive C. perfringens strain in a subclinical necrotic enteritis model. Double vaccination with crude supernatant resulted in a significant decrease in the number of chickens with necrotic enteritis lesions. The efficacy of vaccination using toxoid was lower compared with crude supernatant. Single vaccination with crude supernatant at day 3 resulted in significant protection, while vaccination of 1-day-old chickens with crude supernatant or toxoid, as envisaged for practical field application, did not induce protection.
Assuntos
Animais Recém-Nascidos/imunologia , Galinhas , Infecções por Clostridium/veterinária , Clostridium perfringens/imunologia , Enterite/veterinária , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/prevenção & controle , Vacinação/veterinária , Animais , Animais Recém-Nascidos/microbiologia , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/farmacologia , Infecções por Clostridium/prevenção & controle , Enterite/prevenção & controle , Injeções Subcutâneas/veterinária , Estatísticas não Paramétricas , Vacinação/métodosRESUMO
Housing of breeding does in group pens can result in skin injuries and stress due to maternal protective behaviour and hierarchy fights. Aggression can be partly reduced by using single-litter cages during the first weeks of the reproductive cycle and by delaying the grouping of does with their litters until the kits are older. Hierarchy fights do still occur in these part-time housing systems, however. The present study evaluated the effect of group size and cage enrichment on doe and kit skin injuries and on doe social behaviour. During four cycles, groups of either three or four does with their 22-day-old kits were housed in group pens for 13 days. Pens were assigned one of the following treatments (n = 12 pens per treatment): group of four does with no additional enrichment, four does with additional cage enrichment, three does with no additional enrichment and three does with additional cage enrichment. Cage enrichment was comprised of plastic pipes and elevated platforms. As pen size remained constant, a change in group size also implied a proportional change in stocking density. The number and severity of skin injuries were monitored before grouping and at 1, 3, 6, 9 and 13 days after grouping. Video recordings from all group pens were scored continuously for doe behaviour during the first 24 h after grouping in the first and second reproduction cycle and for the first 8 h in the third cycle. Four severely injured does needed to be removed after grouping. During the first day after group housing, respectively, 72.6 and 13.0% of the does and kits acquired at least one new skin injury with respect to the onset of group housing. Compared with groups of four, does in groups of three had lower averaged skin injury scores (9.41 versus 8.40, P = 0.004). Of all observed postgrouping social behaviours, submissive behaviour was most frequently observed (42.8%), followed by aggressive behaviour (29.8%), engaging behaviour (25.1%) and non-aggressive social contact (2.3%). Does used the enrichment during 11.1% of the total observation time, during which the platforms were more frequently visited (97.2%) in comparison to the plastic pipes (2.8%). As shown by the percentage of injured animals on the last day of grouping (does: 61.9% and kits: 18.4%), postgrouping aggression remains a problem that appears difficult to reduce to acceptable levels by reducing group size (and stocking density) or by providing cage enrichment.
Assuntos
Criação de Animais Domésticos , Abrigo para Animais , Coelhos , Animais , Criação de Animais Domésticos/métodos , Reprodução , Comportamento Social , AgressãoRESUMO
We compared a 3- and 5-phase feeding program in terms of ammonia concentrations measured at litter level, litter composition and quality, nitrogen (N) utilization, performance, welfare, and meat deposition in broilers. A total of 744 Ross 308 male broilers was divided into 2 treatments, each with 6 replicates. The 3-phase diets were formulated to CP and digestible lysine contents of 205 and 11.5 g/kg (0 to 9 d), 195 and 10.8 g/kg (9 to 24 d), and 183.3 and 10.15 g/kg (24 to 39 d), respectively. The 5-phase diets had additional phases from 17 to 24 d and 32 to 39 d with CP and digestible lysine contents of 188 and 10.4 g/kg and 177 and 9.8 g/kg, respectively. Feeding 5 phases reduced the NH3 concentrations at litter level by 37.95% and 20.81% at 23 (P < 0.05) and 37 d of age (P < 0.05), respectively. There was a tendency for a lower litter total ammoniacal nitrogen concentration for the 5-phase treatment than the 3-phase treatment at 24 and 39 d of age (P < 0.1 for both). Total N concentration of the litter also tended to be lower for the 5-phase treatment at 39 d of age (P < 0.1). The lower NH3 coincided with a lower average litter pH at 24 and 32 d of age (P < 0.05 for both). Birds fed the 5-phase treatments had a lower incidence of foot lesions at 24 d of age (P < 0.001). Performance as well as carcass yield could be maintained, except for FCR, which was higher for the 5-phase treatment between 17 and 24 d of age and the overall period (P < 0.05 and < 0.001, respectively). The impact of the 5-phase treatment regarding the utilization of N (digestibility, excretion, and retention) was less clear, however the NH3 volatilized from the litter was significantly reduced. Feeding 5 phases may therefore potentially reduce the NH3 emitted from broiler houses which has several environmental and health benefits. Although the 5-phase treatment resulted in a significant decrease in feed efficiency, growth performance and meat deposition were maintained.
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It is known that high doses of various tannins could impair broiler growth, and this seems to be linked to a lowered protein availability. However, effects on protein digestion under the influence of hydrolysable tannins were minimal in previous research and literature. Other possible proposed reasons to explain reduced growth are scarce. In this experiment we studied the effect of hydrolysable tannins on body allometry by using different feeding schemes throughout the rearing period. In total 112 individually reared male Ross 308 broilers received a 3-phase basal diet with chestnut wood extract (+: 2,000 mg/kg) or not (-: 0 mg/kg) (Tanno-SAN®, Sanluc International NV, Belgium). This resulted in 2 groups during the starter period (S+, S-), 4 groups in the grower period (G++, G+-, G-+, G-) and 8 groups in the finisher period (F+++, F++-, F+-+, F+--, F-++, F-+-, F--+, F--). Similar to previous studies, growth reduction was also observed in this study. Effects were the largest in broilers that were given the tannins during the grower phase. At the end of each phase 8 broilers per group were euthanized and sampled. Liver, pancreas, pectoralis muscle, intestinal weights and intestinal length were recorded. The largest effects were seen on the intestine. Broilers that received tannins during the grower phase, had longer intestines at the end of the finisher period. Furthermore, histological differences between treatment groups were observed at the end of the grower period. Addition of tannins in the grower phase (G-+, G++) resulted in longer villi, whereas addition of tannins in the starter (G+-, G++) caused deeper crypts at the end of the grower phase, with the group (G-+) having the highest villi-to-crypt ratio. These results tentatively prove that tannins influence intestinal growth, both macroscopically as well as histologically. We hypothesize that the observed growth reduction with tannins could be the result of a changed energy and nutrient partitioning, i.e., more nutrients are directed to intestinal growth than for muscle growth.
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Nitrogen (N) excreted by poultry is converted to ammonia (NH3), presenting an environmental risk and a health risk to the farmer and animals. A study was performed to investigate the effect of reduced CP and feed form on broiler performance and welfare, meat and litter quality, N utilization, and NH3 concentrations at litter level. A total of 2,232 Ross 308 male broilers was divided into 6 treatments and 6 replicates, which was fed diets in both pellet and mash forms with different CP levels of 205.0 g/kg (H, high), 187.5 g/kg (M, intermediate) and 175.0 g/kg (L, low) in the grower phase and 195.0 g/kg (H), 180.0 g/kg (M) and 165.6 g/kg (L) in the finisher phase. Individual amino acids (AA) were supplemented to maintain digestible AA-to-digestible lysine ratios. Decreasing dietary CP content to 187.5 g/kg in the grower phase and 180.0 g/kg in the finisher phase reduced NH3 concentrations at litter level (P < 0.001), but a further reduction in dietary CP had no additional effect. Mash treatments had better litter qualities and lower incidences of foot and hock lesions than pellet treatments at d 38 (P < 0.001). In addition, treatments with reduced CP had lower incidence of foot lesions at d 38 (P < 0.001). Broilers fed pelleted diets had higher ADFI, ADG, and final BW, improved feed conversion ratio (FCR), and heavier carcasses (P < 0.001) than those fed mash diets over a production period of 39 d. Performance could not be maintained when birds were fed L CP pelleted diets. This study demonstrated that, with the supplementation of AA to meet requirements, the concentration of dietary CP can be reduced to 187.5 and 180.0 g/kg in the grower and finisher phases respectively, without impairing broiler performance, meat yield and quality. Mash diets were favorable when considering the overall litter quality and welfare of the birds. However, they could not maintain the same broiler performance and slaughter yield as pelleted diets. Results from the present study may assist the poultry sector towards a socially acceptable low-emission farming system.
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The objective of this study was to evaluate the effect of the interaction of the zinc source (ZnSO4 vs. zinc amino acid complex) and vitamin E level (50 IU/kg vs. 100 IU/kg) on meat yield and quality in broilers subjected to chronic cyclic heat stress in the finisher phase. A total of 1224 one-day-old male Ross 308 broilers were randomly distributed among four dietary treatments. Each treatment contained nine replicates of 34 birds, housed in floor pens in a temperature- and lighting-controlled room. Treatments were organized in a 2 × 2 factorial arrangement: two sources of zinc, 60 mg/kg of Zn as ZnSO4 or 60 mg/kg of Zn as zinc amino acid complexes (ZnAA), combined with two levels of vitamin E (50 or 100 IU/kg). From day 28 until day 37 (finisher phase), all birds were subjected to chronic cyclic heat stress (32 ± 2°C for 6 h daily). In the present study, it was observed that replacing ZnSO4 with ZnAA increased breast meat weight and yield of broilers reared under chronic cyclic heat stress conditions, whereas total slaughter yield was not affected. Moreover, it was observed that replacing ZnSO4 with ZnAA resulted in breast meat with a lower drip and thawing loss and a higher marinade uptake. In conclusion, replacing ZnSO4 with more readily available ZnAA can improve breast meat yield and increase the water-holding capacity of breast meat of broilers exposed to chronic cyclic heat stress at the end of the production cycle. However, as no thermoneutral group was included in the present study, the observed effects of the zinc source cannot be generalized as a solution for heat stress. Moreover, the beneficial effects of ZnAA on breast meat yield and quality seem to be independent of the vitamin E level, and increasing vitamin E level has no additional beneficial effects.
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In 2 broiler trials, the effects of chestnut tannins on performance and meat quality (trial 1), and digestion (trial 2) were evaluated. In both trials, Ross 308 broilers received one of 2 basal diets: one basal diet contained corn and soy as main feed ingredients, while the challenge basal diet contained wheat, palm oil, and rapeseed meal. The composition of the basal diets was chosen to assess the interaction between chestnut tannins and diet composition. To both basal diets, chestnut tannins were added at 3 doses: 0 mg/kg (T-), 500 mg/kg (T+), or 2,000 mg/kg (T++), resulting in a total of 6 treatments. In trial 1, both basal diets containing 2,000 mg/kg chestnut tannins lowered broiler performance in grower and finisher phases. A tannin dose of 500 mg/kg had no effect on performance in either basal diet. Corn-based diets resulted in lower meat pH compared to wheat diets. Further, addition of chestnut tannins resulted in increased meat pH, and caused proportionally a lower meat drip loss and shear force for both basal diets. During the digestibility study (trial 2), blood was also collected. None of the treatments affected digestibility or blood parameters (glucose, non-esterified fatty acids, and triacylglycerols). Malondialdehyde (MDA) was measured in plasma to assess antioxidative properties of chestnut tannins. In wheat diets, chestnut tannins significantly lowered plasma MDA demonstrating its antioxidative nature. Regarding gut health, crypt depth decreased proportionally with the dosage of chestnut tannins in both basal diets with significantly shallower crypts for the wheat diets compared to the corn diets. Relative intestinal growth was stimulated in the wheat diets proportionally to the tannin dose based on the larger relative gut length. In conclusion, chestnut tannins did not influence digestive metabolism, yet they lowered performance at higher doses regardless of feed ingredients used in the diet. Tannins positively affected meat quality and when added to wheat diets, intestinal growth was stimulated and the antioxidative status of the broilers improved.
Assuntos
Galinhas , Taninos , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Suplementos Nutricionais , Digestão , Carne/análise , NutrientesRESUMO
Zinc is an essential nutritional trace element for all forms of life as it plays an important role in numerous biological processes. In poultry, zinc is provided by in-feed supplementation, mainly as zinc oxide or zinc sulfate. Alternatively zinc can be supplemented as organic sources, which are characterized by using an organic ligand that may be an amino acid, peptide, or protein to bind zinc and have a higher bioavailability than inorganic zinc sources. There are limited number of studies directly comparing the effects of inorganic vs. organic zinc sources on performance and intestinal health in broilers. Therefore, a digestibility and a performance study were conducted to evaluate and compare the effect of an amino acid-complexed zinc source vs. an inorganic zinc source on intestinal health. The experiment consisted of 2 treatments: either a zinc amino acid complex or zinc sulfate was added to a wheat-rye based diet at 60 ppm Zn, with 10 replicates (34 broilers per pen) per treatment. Effects on performance, intestinal morphology, microbiota composition, and oxidative stress were measured. Supplementing zinc amino acid complexes improved the zinc digestibility coefficient as compared to supplementation with zinc sulfate. Broilers supplemented with zinc amino acid complexes had a significantly lower feed conversion ratio in the starter phase compared to birds supplemented with zinc sulfate. A significantly higher villus length was observed in broilers supplemented with zinc amino acid complexes at days 10 and 28. Supplementation with zinc amino acid complexes resulted in a decreased abundance of several genera belonging to the phylum of Proteobacteria. Plasma malondialdehyde levels and glutathione peroxidase activity showed an improved oxidative status in broilers supplemented with zinc amino acid complexes. In conclusion, zinc supplied in feed as amino acid complex is more readily absorbed, potentially conferring a protective effect on villus epithelial cells in the starter phase.
Assuntos
Galinhas/metabolismo , Intestinos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Zinco/metabolismo , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Relação Dose-Resposta a Droga , Intestinos/anatomia & histologia , Intestinos/fisiologia , Masculino , Distribuição Aleatória , Zinco/administração & dosagemRESUMO
Viscosity of intestinal contents is known to affect digestion and absorption of nutrients. In most poultry studies, intestinal viscosity has been measured only after complete removal of solid particles by centrifugation. Centrifugation may however remove particles that contribute to viscosity, hence giving rise to an underestimation of viscosity. Two viscosity measurement techniques, one including a centrifugation step (Brookfield) and the other without (Haake), were compared in-vitro to assess whether both techniques result in similar conclusions regarding viscosity in feedstuffs. Two sets of feedstuff preparations were used. The first set was prepared with different combinations of milled feedstuffs in order to have a wide range of viscosity: 100% corn, 25% corn + 75% wheat, 100% wheat, 90% wheat + 10% rye, all mixed with distilled water. In the second set, barley was incubated with different beta-glucanases, and soybean and sunflower meal were incubated with different pectinases, again all mixed with distilled water. Viscosity was assessed using both techniques (Haake and Brookfield equipments) at six different time points. To evaluate the extent of agreement between the two methods, the Lin's concordance correlation coefficient (CCC) was assessed using the percentage of increase in viscosity within each method, based on pairwise feedstuffs comparison (first set), or relative to the feedstuff without enzyme (second set). The rate of the agreement between the two methods was substantial for the first set of feedstuffs (66%) and for the barley diets incubated with beta-glucanases (69%), whereas the CCC score for the soybean meal diets was very poor (2%) and fair for the sunflower meal diets, incubated with pectinases (32%). The lack of agreement for the latter can be explained by the limited variation in viscosity in these low-viscous mixtures. Although the two techniques are considerably different (e.g., with or without preceding particle removal), they seem to render similar conclusions when applied to poultry feedstuffs to identify distinct differences under the tested circumstances.
Assuntos
Ração Animal/análise , Criação de Animais Domésticos/métodos , Conteúdo Gastrointestinal/química , Criação de Animais Domésticos/instrumentação , Animais , Centrifugação , Aves Domésticas , ViscosidadeRESUMO
The pre-slaughter phase of the production process has potentially important animal welfare implications, including mortality (recorded as "Dead on Arrivals"; DOA: ). To reduce DOA%, specific risk factors need to be identified. DOA% can also be used as a first and quick screening of pre-slaughter broiler welfare under commercial conditions. The aim of the present study was to identify risk factors for DOA% in commercial broiler flocks and to find associations between DOA% and animal-based indicators of broiler welfare during the pre-slaughter phase. Eighty-one transported flocks to five slaughter plants were assessed. Farmers provided information on the flock and observers gathered data on pre-slaughter factors. DOA% was recorded by slaughter plant personnel. The association between risk factors and DOA% was tested using linear mixed models, with slaughter plant as the random effect. Mean (± SE) DOA% was 0.30 ± 0.05% and median was 0.19% (range 0.04 to 3.34%). Two risk factors for DOA% were identified, both related to flock health status during the production phase. Higher DOA% was found when farmers did not check chick quality upon arrival (P = 0.011), although one extreme DOA% caused this significant effect. In addition, on-farm mortality during production (including selective culling) was negatively associated with DOA% (P = 0.011), potentially due to the selective culling on farm. Further research is needed on the impact of on-farm health status on welfare during the pre-slaughter phase, as the current study provided some evidence that on-farm factors are linked to mortality during the pre-slaughter phase. No specific characteristics of the pre-slaughter phase could be identified as risk factor for increased mortality. DOA% was positively associated with five welfare indicators, including indicators of thermal stress, which indicates the potential to use DOA% as a quick, cost-efficient screening tool for those welfare aspects.
Assuntos
Matadouros , Criação de Animais Domésticos/estatística & dados numéricos , Bem-Estar do Animal , Galinhas/fisiologia , Mortalidade , Meios de Transporte , Animais , Bélgica , Modelos Lineares , Fatores de RiscoRESUMO
Before broilers are slaughtered, several parties are involved in catching, loading, transportation and lairage. During these pre-slaughter activities, broilers are exposed to a variety of stressors. A detailed understanding of how broiler welfare is impaired during each stage could help the responsible parties to make targeted improvements. The aim of this study was to identify welfare problems occurring during the consecutive stages of commercial broiler transportation and to identify risk factors associated with the identified welfare problems. Commercial Belgian transports (n = 81) were assessed in spring (n = 14), summer (n = 33), autumn (n = 10), and winter (n = 24), and potential risk factors were recorded by the observer. Animal-based welfare indicators were scored before the start of the pre-slaughter phase as well as after the catching, transport and lairage, and slaughter stages to assess the impact of each stage. The most frequently observed welfare impairments were vent and thigh lesions, panting, wing fractures, and bruising on wings and breasts. Our results show that the impact of the pre-slaughter phase on broiler welfare is multifaceted. The overall pre-slaughter phase resulted in a mean weight decrease of 5.3%, a prevalence of 1.4% in leg bruising, and 3.7% in breast or wing bruising. Wing fractures occurred mainly during the catching stage: Prevalence increased from 0.1% to 1.9% (P = 0.003). A welfare comparison before and after transportation and lairage revealed that plumage had become more soiled (P = 0.003), body temperature decreased by 0.7°C (P < 0.001), huddling prevalence increased by 0.5% (P = 0.008), prevalence of birds with splayed legs increased by 0.08% (P = 0.008), prevalence of supine birds decreased by 0.05% (P = 0.003), and 0.1% fewer birds with wings stuck in the crates (P = 0.010) were observed. Risk factor analyses revealed that carefully choosing the catching crew, minimizing thermal stress, reducing duration of transportation, and worker training are promising actions that may improve broiler welfare during the pre-slaughter phase.