Battery Cages Research Articles

The Caged Chicken or the Free-Range Egg? The Regulatory and Market Dynamics of Layer-Hen Welfare in the UK, Australia and the USA

Since the 1990s there have been a number of government and market led initiatives to improve the welfare of layer hens in the United Kingdom, Australia and the USA. The focus of these regulatory and market initiatives has been a shift away from the dominant battery-cage system to enriched cages, barn/aviary and free-range production systems. Government regulations have played an important role in setting some minimum welfare standards and the banning of battery cages in the UK and in some US states. However the commodification and market segmentation of higher welfare standards has also seen the growth in production and demand of cage-free and free-range eggs in all three countries. This paper maps and compares the developments in government regulation and market segmentation of layer-hen welfare in the UK, Australia and the USA. The role of labelling and certification in facilitating commodification and market segmentation will be examined, including the public controversies and legal conflicts over egg labelling. The key state, market and civil society actors in each country will also be identified, and their role in driving or resisting higher standards examined, including the increasingly influential role of animal welfare organizations and food corporations.

Osteopenia: a disease of laying hens with major impact on production and welfare

Osteopenia is a significant disease of the skeleton in mature chickens used for egg production. It characteristically occurs in lines of laying hens with high rates of egg production and can be regarded as a generalised skeletal disorder resulting in bone fractures. Since the condition was first recognised, the scale of the problem has increased. It was estimated that in commercial flocks in the United States approximately 15-30% of hen mortality is related to osteopenia. The condition is divided into two forms: peracute, where death occurred with the onset of symptoms and acute, where the birds survived the initial collapse. The condition was first known as 'Cage Layer Fatigue', but terms such as 'Cage Layer Paralysis' and 'Cage Layer Osteoporosis' are also used. Nowadays there are three different terms which are used to describe poor bone condition. Osteopenia is a less specific term, which describes a loss in the amount of bone tissues leading to bone fragility without implying whether or not bone density is involved. Osteomalacia is caused by defective mineralisation of bone tissue and is characterised primarily by thick seams of unmineralised or poorly mineralised organic matrix on the surfaces of medullary bone trabeculae. In osteoporosis there is a decrease in the amount of bone tissue, the matrix of which is normally mineralised. Production problems and financial losses to the producer are caused by osteopenia affecting at the same time the welfare of the birds. Pain and distress associated with broken bones and healed or new fractures obviously compromise the welfare of the birds. There are also production problems, associated firstly with mortality and lost production in battery hens and secondly in the processing of spent layers where bone breakage results in the contamination of carcasses and recovered meat with splinters of bone. Losses to the poultry industry that result from cracked and broken eggs are very considerable and it is very important for the producer to maximise the difference between the value of saleable outputs and nutritional costs. Therefore, the relationships between dietary calcium, bone components, eggshell formation and their consequences, which might result from an imbalance between them (e.g. osteopenia, decreased shell quality), strongly affect the finalprofit of a laying flock and the income of the producer. The causes of osteopenia are divided into immediate - osteomalacia andosteoporosis -and predisposing causes, such as genetic, nutritional and husbandry effects. Calcium, phosphorus, vitamin D deficiencies or imbalance of the calcium/phosphorus ratio in the diet can induce osteomalacia, whereas osteoporosis maybe relatedwith hormonal changes, lack of exercise and age-related effects. Factors, such as age at sexual maturity, body weight, medullarybone and various pharmaceutical and nutritional factors, may also strongly influence bone strength. Osteopenia is largely geneticin origin, resulting from the breeding of light weight, energetically efficient birds that remain in a high rate of lay for a prolongedperiod. Thus, a genetic solution to the problem seems to be possible. Further and immediate improvement in bone strength is likely to come from husbandry and nutritional practices. Husbandry modifications have been proven very influential on improving or reducing bone strength. Nutritional techniques have been the most commonly adopted in an attempt to reduce the severity of osteopenia. By modifying the diet, the beneficial or non-beneficial effects of the various experimental trials on bone strength could be immediate and cost-effective compared with genetic and husbandry modifications.

Insights and challenges of Salmonella infection of laying hens

Salmonella infection of laying hens and subsequent contamination of eggs continues to be a public health concern. The focus of this review is to discuss some of the current and future issues that impact Salmonella association with laying hens and egg contamination. Among these issues are the impact of shifting to alternative cage free layer hen housing and away from cage batteries. Most of the focus will be on Salmonella Enteritidis as the serotype primarily associated with laying hens and the mechanisms that ensure its successful colonization, infection and subsequent contamination of table eggs. The variability in virulence and survival characteristics among S. Enteritidis strains will also be discussed including studies on detailed characterization at the molecular level. Finally, the comprehensive assessment of the laying hen gastrointestinal tract microbiota to better understand S. Enteritidis colonization and the subsequent host response will be examined.

RNA-Seq de novo assembly and differential transcriptome analysis of the nematode Ascaridia galli in relation to in vivo exposure to flubendazole.

The nematode Ascaridia galli (order Ascaridida) is an economically important intestinal parasite responsible for increased food consumption, reduced performance and elevated mortality in commercial poultry production. This roundworm is an emerging problem in several European countries on farms with laying hens, as a consequence of the recent European Union (EU) ban on conventional battery cages. As infection is associated with slow development of low levels of acquired protective immunity, parasite control relies on repeated use of dewormers (anthelmintics). Benzimidazoles (BZ) are currently the only anthelmintic registered in the EU for use in controlling A. galli and there is an obvious risk of overuse of one drug class, selecting for resistance. Thus we developed a reference transcriptome of A. galli to investigate the response in gene expression before and after exposure to the BZ drug flubendazole (FLBZ). Transcriptional variations between treated and untreated A. galli showed that transcripts annotated as mitochondrial glutamate dehydrogenase and cytochrome P450 were significantly down-regulated in treated worms, whereas transcripts homologous to heat shock proteins (HSP), catalase, phosphofructokinase, and a multidrug resistance P-glycoprotein (PGP1) were significantly up-regulated in treated worms. Investigation of candidate transcripts responsible for anthelmintic resistance in livestock nematodes led to identification of several tubulins, including six new isoforms of beta-tubulin, and several ligand-gated ionotropic receptors and ABC-transporters. We discovered several transcripts associated with drug binding and processing genes, but further characterisation using a larger set of worms exposed to BZs in functional assays is required to determine how these are involved in drug binding and metabolism.

Phenotypic and Genotypic Features of a Salmonella Heidelberg Strain Isolated in Broilers in Brazil and Their Possible Association to Antibiotics and Short-Chain Organic Acids Resistance and Susceptibility.

Salmonella enterica serovar Heidelberg is a human pathogen also found in broilers. A strain (UFPR1) has been associated with field reports of resistance to short-chain organic acids (SCOA) in broilers in the South of Brazil, but was susceptible to a Bacillus subtilis-based probiotic added in feed in a related study. This work aimed to (i) report clinical symptoms caused by SH UFPR1 in broilers, (ii) study its susceptibility to some antibiotics in vitro, and (iii) SCOA in vivo; and (iv) relate these phenotypic observations with its genome characteristics. Two in vivo trials used 1-day-old chicks housed for 21 days in 8 sterilized isolated negative pressure rooms with 4 battery cages of 12 birds each. Birds were challenged or not with 107 CFU/bird of SH UFPR1 orally and exposed or not to SCOA in a 2 × 2 factorial design. Zootechnical parameters were unaffected (P > 0.05), no clinical signs were observed, and few cecal and hepatic histologic and immune-related alterations were seen, in birds challenged with SH. Formic and propionic acids added together in drinking water, fumaric and benzoic acid in feed (Trial 1), and coated calcium butyrate in feed (Trial 2) did not reduce the SH isolation frequencies seen in cecum and liver in broilers after SH challenge (P > 0.05). SH UFPR1 was susceptible to amikacin, amoxicillin + clavulanate, ceftiofur, cephalexin, doxycycline and oxytetracycline; and mildly susceptible to ampicillin + sulbactam, cephalothin, ciprofloxacin, enrofloxacin, and gentamycin in an in vitro minimum inhibitory concentration model using Mueller–Hinton agar. The whole genome of SH UFPR1 was sequenced and consisted of a circular chromosome, spanning 4,760,321 bp with 52.18% of GC-content encoding 84 tRNA, 22 rRNA, and 4,427 protein-coding genes. The comparison between SH UFPR1 genome and a multidrug-resistant SL476 strain revealed 11 missing genomic fragments and 5 insertions related to bgt, bgr, and rpoS genes. The deleted genes codify proteins associated with cell cycle regulation, virulence, drug resistance, cellular adhesion, and salt efflux which collectively reveal key aspects of the evolution and adaptation of SH strains such as organic acids resistance and antibiotic sensitivity and provide information relevant to the control of SH in poultry.

Feeder space affects access to the feeder, aggression, and feed conversion in laying hens in an aviary system

In laying hens, minimal requirements for feeder space (cm per bird) are based primarily on data from small groups of hens (n<10) housed in battery cages. The aim of the present study was to determine the effects of feeder space on agonistic behaviour, access to the feeder, and production in laying hens housed in an aviary system. The experiment was conducted in a quasi-commercial barn that contained 20 pens with 200 Lohmann Selected Leghorn hens housed in each. Five levels of feeder space (3.8, 6.0, 8.0, 9.0, and 10.0cm/hen) were systematically allocated to four pens each from 21 weeks of age onwards. Behavioural assessments from video recordings at 21, 32, 39, and 45 weeks of age included: aggression, jostling followed by either feeding or other behaviour, duration of feeding bouts, and the number of hens feeding from the perch above the feeder as well as simultaneously from the platform at the feeder. Production parameters were measured daily and included: egg production, floor eggs, feed disappearance, and feed conversion ratio. Our results show that more feeder space was associated with less aggression (z-value=−4.06, p<0.001) and less jostling (followed by feeding: z-value=−3.74, p<0.001; followed by other behaviour: z-value=4.24, p<0.001), as well as more simultaneous feeding from the platform at the feeder (z-value=−5.36, p<0.001) and longer feeding bouts (z-value=4.68, p<0.001). Feed disappearance (t-value=3.08, df=18, p=0.006) increased and feed conversion decreased with feeder space (t-value=2.245, df=18, p=0.038). The results indicate positive effects of increased feeder space on laying hen behaviour at the cost of relatively minor production losses. Thus, competition at the feeder decreased with increasing feeder space, allowing more birds to feed simultaneously, while feed conversion decreased only slightly. By combining measures of behaviour and production, our results can facilitate decisions on feeder space for laying hens in view of optimal trade-offs between agonistic behaviour, access to the feeder, and feed conversion.

EVALUATION OF SPIRULINA ALGAE (SPIRULINA PLATENSIS) AS A FEED SUPPLEMENT FOR JAPANESE QUAIL: NUTIRITIONAL EFFECTS ON GROWTH PERFORMANCE, EGG PRODUCTION, EGG QUALITY, BLOOD METABOLITES, SPERM-EGG PENETRATION AND FERTILITY

This study aimed to evaluate the nutritional impacts of Spirulina platensis supplementation in the feed and drinking water of the Japanese quail during the growing and laying periods. One-hundred-twenty Japanese quails (14 days old) were housed in twelve battery cages, which were randomly corresponded to three treatments: a basal mash diet (BMD) (control group), a BMD plus 1% Spirulina platensis, and a BMD plus 0.25% of Spirulina in the drinking water. The growth performance was evaluated between the 2nd and 6th week of age, then the egg production parameters and fertility rates were investigated during the following seven weeks. The Spirulina powder used in this study had 95.40% dry matter, 54.70% crude protein, 2.58% ether extract, and 1.58% crude fiber. During the growing period, the results showed that the birds provided with Spirulina powder at 1% in the feed (T1) and at 0.25% in the drinking water (T2) had higher (P<0.05) body weight (BW) and body weight gain (BWG) values than those of the control group. The total FI of T1 was higher (P<0.05) than those of the control and T2 (505.1 vs. 515.6 and 504.9 g). Besides, both of Spirulina treatments had better feed conversion ratios than that of the control group (3.3 and 3.3 versus 3.6 feed: gain). During the laying period, the Spirulina supplementation in feed or in water did not show significant (P≥0.05) effects on the egg laying rate, egg weight, daily egg mass, feed intake, feed conversion (g feed: g egg) as compared with the control group. Finally, the birds supplemented with Spirulina treatments had lesser serum cholesterol and free fatty acid levels, and displayed higher fertility values (P<0.05) than that of the control group. In conclusion, the addition of Spirulina to the feed and/ or to the drinking water of the Japanese quail had beneficial effects on growth performance and fertility, while it did not show any significant (P≥0.05) impact on the egg production, egg quality, or dressing percentage.

Comparative Efficiency of Table Egg Farms Under Two Different Production Systems in Oyo State, Nigeria

This study was a comparative economic analysis of poultry egg production under different production systems in Oyo State, Nigeria. Primary data were collected with the aid of a structured questionnaire from 134 (75 battery cage and 59 deep litter systems) poultry farmers through a multistage sampling procedure in three agricultural zones of the State. Descriptive statistics, budgetary techniques, Data Envelopment Analysis (DEA), Tobit regression and student-t test methods were used to analyze the data. Results showed that the mean ages of the farmers were 44 and 40years for battery cage and deep litter systems respectively, while 97.3% and 97.0% of battery cage and deep litter system users had formal education respectively. Also, 78.9% and 88.1%; 65.3% and 57.6%; 25.3% and 28.8% of battery cage and deep litter users were male, members of cooperative society and had extension contacts respectively while 57.3% and 76.3%; 86.7 and 84.8% of battery cage and deep litter users used Isah Brown breed and commercial feed respectively. The Net Farm Incomes (NFI) per bird for battery cage system were ₦2,052.17; ₦1,282.86 and ₦1,605.28 while that of deep litter system were ₦1,897.84; ₦1,467.46 and ₦1,236.06 for small, medium and large scale farmers respectively. DEA revealed that the mean technical efficiencies for battery cage and deep litter systems were 0.892 and 0.912. Tobit regression revealed that the determinants of technical efficiency of farmers using battery cage system were extension visits (p<0.01); gender (p<0.01); farmers’ years of education (p<0.05) and membership of cooperative society (p<0.05). Also, the efficiency of farmers using deep litter system was influenced by breed of bird (p<0.01); feed type (p<0.01) and gender (p<0.01). This study concluded that there is no efficiency loss in the choice of either of the systems, except that expansion may be restricted in deep liter system if land constraints exist. The study recommended that farmers who wish to invest in poultry egg production are at liberty to choose either of the systems depending on the intended scale of production.

431 Effect of dietary mercury concentrations on growth performance and relative organ weight in female broiler chickens

An experiment was conducted to investigate the effect of dietary mercury concentrations on growth performance and relative organ weight in female broiler chickens. A total of 400 2-d-old Ross 308 female broiler chicks were housed in 40 battery cages for a 5-wk feeding trial. Birds were randomly allotted to 1 of 5 dietary treatments with 8 replicated cages. Each replicate had 10 birds per replicate. Dietary mercury concentrations were set to 0, 50, 100, 250, or 500 mg/kg by adding mercury chloride (≥ 73.9%) at the expense of the celite. At the conclusion of the experiment, 1 bird per replicate with a body weight (BW) close to the replicate mean BW (i.e., 8 birds per treatment) were euthanized by CO2 asphyxiation, then immediately dissected. The breast, liver, heart, kidney, spleen, lung, bursa of Fabricius, and small intestine were collected and weighed individually. Relative organ weight was expressed as a percentage of live BW. Results indicated that increasing mercury concentrations in diets decreased BW gain (linear and quadratic, P < 0.05) and feed intake (linear, P < 0.01) of female broiler chickens. Birds fed diets containing 500 mg/kg mercury showed less (P < 0.05) body weight gain and feed intake than those fed the control diets. However, there were no differences in feed efficiency and mortality among dietary treatments. The relative weight of the liver was increased (linear, P < 0.05) with increasing mercury concentrations in diets. There was a quadratic relationship (P < 0.01) between the relative weight of the small intestine and increasing mercury concentrations in diets. In conclusion, the concentrations of 500 mg/kg mercury in diets are toxic to female broiler chickens. The liver is likely the most sensitive organ to the toxic concentrations of mercury in diets for female broiler chickens.

Apparent metabolisable energy and ileal crude protein digestibility of various treated palm kernel cake based diets for heat-stressed broiler chickens

Summary A digestibility trial was conducted to determine the apparent metabolisable energy (AME) and apparent ileal digestibility (AID) of crude protein in broilers fed various treated palm kernel cake (PKC) based diets under unheated and heated conditions. A total of 240 day-old female broiler chicks (Cobb 500) were randomly distributed to 60 battery cages in environmentally controlled rooms and fed standard broiler diets from day 1 to 28. From day 29 to 35, chickens were assigned to one of the following 6 diets: (1) 25% untreated PKC, (2) 25% shell-less PKC (SPKC), (3) 25% enzyme treated PKC (EPKC), (4) 25% extruded PKC (XPKC), (5) 25% extruded shell-less PKC (XSPKC) or (6) 0% PKC (control). From day 29–35, equal numbers of birds from each diet were exposed to either 24 ±Â 1°C (unheated) or 34 ±Â 1°C for 6 h daily (heated).

Effects of coccidiosis vaccination administered by in ovo injection on Ross 708 broiler performance through 14 days of post-hatch age

Effects of the in ovo injection of a commercial coccidiosis vaccine on various hatching chick quality variables and 14 d post-hatch (dph) oocyst shedding have been previously examined. The current study was designed to examine the performance of Ross 708 broilers during the 14 dph period of oocyst shedding following the application of the coccidiosis vaccine. On each of 7 replicate tray levels of a single-stage incubator, a total of 4 treatment groups was randomly represented, with each treatment group containing 63 eggs. Treatments were administered using a commercial multi-egg injector on d 18.5 of incubation. The treatments included 3 control groups (non-injected, dry-punch, and diluent-injected) and one treatment group (injected with diluent containing Inovocox EM1 vaccine). On d 21 of incubation, 20 chicks from each of the 28 treatment-replicate groups were placed in corresponding wire-floored battery cages. Mortality, feed intake (FI), BW gain (BWG), and feed conversion ratio (FCR) were determined for the zero to 7, 7 to 14, and cumulative zero to 14 dph intervals. There were no significant treatment effects on mortality in any interval or on BW at zero dph. There were significant treatment effects on BW at 7 and 14 dph, on BWG and FI in the zero to 7, 7 to 14, and zero to 14 dph intervals, and on FCR in the 7 to 14 and zero to 14 dph intervals. Although the performance variables of birds belonging to the diluent-injected and vaccine-injected groups were not significantly different, the 14 dph BW, 7 to 14 dph FI, and zero to 14 dph BWG and FI of birds belonging to the vaccine treatment group were significantly higher than those in birds belonging to the non-injected control group. It was concluded that use of the Inovocox EM1 vaccine in commercial diluent has no detrimental effect on the overall post-hatch performance of broilers through 14 dph.

Effect of the Addition of Saccharomyces Cerevisiae Yeast Cell Walls to Diets with Mycotoxins on the Performance and Immune Responses of Broilers.

This study was conducted to evaluate the effect of Saccharomyces cerevisiae yeast cell walls (YCWs) in diets with low doses of aflatoxin B1 (AFB1) and ochratoxin A (OTA), alone or in combination, on broiler performance and immune response. A total of 210 male broilers aged 1–21 days were used. Broilers were completely randomized into seven treatments with five replicates of six broilers each, as follows: 1) control diet; 2) control + 350 µg/kg AFB1; 3) Control + 350 µg/kg OTA; 4) Control + 350 µg/kg AFB1 and 350 µg/kg OTA; 5) Control + 350 µg/kg AFB1 and 1.5 kg/ton YCW; 6) control + 350 µg/kg OTA and 1.5 kg/ton YCW; 7) control + 350 µg/kg AFB1, 350 µg/kg OTA, and 1.5 kg/ton YCW. The broilers were housed under environmentally controlled conditions in Petersime battery cages. Weight gain, feed intake, and feed conversion index were measured. The relative weights of the thymus, spleen, and bursa of Fabricius (BF) were evaluated. The local immune response was assessed by quantifying the level of intestinal immunoglobulin A (IgA). The cellular immune response was evaluated using a delayed hypersensitivity test. Hemograms and blood cell counts were also performed. The results showed that mycotoxins decreased performance and reduced the immune response (p<0.05) of broilers. Weight gain and feed conversion improved in the groups receiving YCWs. The YCWs increased (p<0.05) intestinal IgAs and the cellular immune response (p<0.05). The addition of YCWs also affected the relative weight of the thymus, spleen, and BF (p<0.05), and the leukocyte, lymphocyte, and heterophil counts (p<0.05). The addition of YCWs can be an alternative to counterage the negative effect of low doses of AFB1 and OTA in broilers diets.

A new era of UK leadership in farm animal welfare

For over 50 years the UK has shown leadership in public-driven animal welfare policy and, more recently, consumer-focused initiatives. Now that we are leaving the European Union, what should be...

Comparing quality of free range and battery cage eggs

Summary Quality parameters of eggs from laying hens kept in free-range respectively battery cage systems were compared. Lohmann Brown laying hens (n = 75) from 24 to 30 wk of age were used in the study. Feed and water were available ad libitum for both systems. Lightning was applied via a photovoltaic system planned to benefit from solar energy for the free range system. Eggs were sampled at 14-day intervals, interior and exterior quality parameters were recorded.

Bacillus subtilis s train specificity affects performance improvement in broilers

The study reports the effects on broiler performance of a newly isolated Bacillus subtilis strain, which is phylogenetically not closely related to already well-described strains of B. subtilis. In the first experiment, birds were reared in battery cages and exposed to C. perfringens. An increase in growth performance was observed with the strain when compared to the challenged animals. Three additional growth trials were conducted to 35 d of age, in different rearing conditions (genetic breeds, corn-soybean meal-based diet with or without animal proteins, in presence or absence of phytase, on fresh or used litter) to investigate the efficacy and the specificity of this new B. subtilis strain on the improvement of BWG and FCR of broilers in comparison with a B. subtilis-based DFM already used in the field. Whatever the rearing conditions tested, the new B. subtilis strain led to an average 3.2% improvement in feed conversion ratio or bodyweight. Comparatively, the commercial Bacillus strain significantly improved broiler performance in only one trial out of 3 with an average improvement reaching 2%. All these results indicate that this new B. subtilis strain consistently improves broiler performances.

GROWTH PERFORMANCE, CARCASS TRAITS AND SOME BLOOD PARAMETERS OF BROILER CHICKS AS AFFECTED BY HOUSING SYSTEM

This current investigation was conducted to evaluate the potential effects of housing system (battery cages versus litter floor) on growth performance, some blood parameters and carcass characteristics of broilers. A total number of 224 unsexed one day old Evian broiler chicks were randomly distributed into two treatment groups (112 per each group). Chicks of the 1st group were raised in cages, while those of the second one were raised on litter floor. The results of the present work could be summarize as follows: broilers reared on litter floor exceeded (P≤0.05 and 0.01) those kept in battery cages in each of body weight, daily body weight gain and feed consumption in most of the studied intervals. Each of feed conversion ratio, carcass characteristics, some blood parameters and some immunity agents were not significantly changed between broilers kept in batteries and those reared on litter floor. The present work revealed a better performance and an increase in carcass yield of birds reared on floor system, which could be recommended to increase broilers performance under Sharkia Governorate conditions.

Gut microbiota and transportation stress response affected by tryptophan supplementation in broiler chickens

Stimulation of serotonergic activity by tryptophan (TRP) supplementation is known to influence behavioural and physiological processes. One hundred and twenty male broiler chicks were assigned in groups of 5–24 battery cage and fed experimental diets with 0.22, 0.42 and 0.62% of digestible TRP during 21–42 d. On 42 d, birds were challenged with 2 h of transportation stress and samples were collected before or after the transportation. The results revealed that TRP increased feed intake, but had no significant effect on growth performance. Regardless of transportation, heat shock protein 70 (HSP70) and corticosterone (CORT) decreased and serotonin (5-HT) elevated by increasing TRP level in diet. Breast muscle pH and colour were not affected by elevation in dietary TRP, but drip loss decreased and shear force increased. Quantification of gut microflora showed that supplementation of TRP increased Enterococci, and Bifidobacteria populations, while E. coli, Clostridia, Campylobacter and Enterobacteria populations decreased. The effect of diet on Lactobacilli population was not significant. In conclusion, feeding broilers with higher levels of TRP improves their welfare condition both before and after transportation stress, as measured by lower serum CORT and HSP70 and higher 5-HT. Increasing dietary TRP level may shift the balance of pathogenic/non-pathogenic bacteria in gut to a favourable state.

The effect of calcium and magnesium supplementation on performance and bone strength of broiler chickens

Aim of the experiment was evaluation of the effect of reduced calcium and magnesium content in the broiler chickens diet on its parameters of fattening, bone strength and calcium and magnesium content in liver. The trial was performed with cockerels of Ross 308 hybrid (n = 160) which were fattened in cage batteries from day 11th to 36th day of age. Cockerels were divided into 4 groups (differ in various intake levels of calcium and magnesium) in four replications. The maize-wheat-soybean basal diet contained 2.33 g Ca and 1.58 g Mg per kilogram. Calcium was added by CaCO3 and magnesium by MgSO4. Control group (C) received feed mixture with added CaCO3 in dose of 19.49 g.kg-1 and 0.41 g.kg-1 of MgSO4. Three experimental groups contain added CaCO3 in dose of 11.83 g.kg-1 and 0 g.kg-1 MgSO4 (group Exp1); CaCO3 11.83 g.kg-1 and 0.41 g.kg-1 MgSO4 (group Exp2); CaCO3 19.49 g.kg-1 and 0 g.kg-1 MgSO4 (group Exp3), respectively. The feed consumption was daily monitored and the cockerels were weighed twice a week. At the end of the study the experimental animals were weighted and slaughtered by decapitation. The weight of carcasses, liver and proportion of breast and thigh muscle was determined in the selected chickens (n = 24). The atomic absorption spectrometry was used for Ca and Mg evaluation in liver tissues. Bone strength parameter was measured at the femur bone. The statistically significant differences (p &gt;0.05) were not detected between control and experimental groups in the case of studied parameters of fattening, bone strength and calcium and magnesium content in the chicken´s liver. Based on the obtained results it could be concluded the reduction of determined elements in the chicken diet did not deteriorate parameters of yield, elements content in liver tissue as well as the bone strength of broiler chickens.

Effects of dietary copper and amino acid density on growth performance, apparent metabolizable energy, and nutrient digestibility in Eimeria acervulina-challenged broilers

The objective of this experiment was to evaluate the influence of copper supplementation in diets varying in amino acid (AA) density on growth performance, apparent metabolizable energy (AMEn), apparent ileal nutrient digestibility (AID), and plasma carotenoids in broilers infected with Eimeria acervulina. Ross 308 male broilers (480 total) were housed in battery cages and allotted to 8 experimental treatments in a factorial arrangement of 2 dietary AA densities [1.00% (LAA) or 1.20% (HAA) digestible Lys], 2 supplemental copper concentrations (zero or 116 mg/kg), and 2 E. acervulina infection states (uninfected or infected). Essential AA ratios relative to digestible Lys were similar in both the LAA and HAA diets, and copper was provided by 200 mg/kg of tribasic copper chloride (58% copper). Chicks received experimental diets from 2 to 21 d post hatch and 6 replicate cages of 10 birds per cage were assigned to each treatment. Broilers were inoculated with zero or 6.3 × 105 sporulated E. acervulina oocysts at 15 d and blood and ileal digesta were collected at 21 days. From 2 to 15 d, body weight gain and G:F of broilers were improved (P < 0.05) with increasing AA density, and an AA density × copper interaction was observed (P < 0.05) for feed intake. Eimeria infection reduced (P < 0.05) plasma carotenoids, growth performance, dietary AMEn, and AID of organic matter, nitrogen, and total AA. There were no interactive effects of dietary treatments with E. acervulina infection on broiler growth performance or dietary AMEn. An AA density × copper supplementation interaction was observed (P < 0.05) for AID of total AA, whereby copper supplementation increased AID of total AA for birds fed the LAA diet and decreased AID of total AA for birds fed the HAA diet. In summary, E. acervulina-induced reductions in nutrient digestibility were dependent on dietary copper and AA status, but changes in digestibility had minimal impact on growth performance of broilers during the E. acervulina infection period.

Methodology affects measures of phosphorus availability in growing broilers: Effects of calcium feeding strategy and dietary adaptation period length on true ileal phosphorus digestibility and predicted endogenous phosphorus losses

An experiment was conducted to determine the effects of Ca feeding strategy and dietary adaptation period length (DAPL) on the apparent ileal P digestibility (AIPD) and apparent ileal myo-inositol 1,2,3,4,5,6 hexakis dihydrogen phosphate (IP6) hydrolysis (AIIP6H) of corn titration diets. Nine hundred sixty Ross × Ross 708 male broiler chicks were placed into 80 battery cages. Broilers received a common starter diet until 18 d of age and then were fed one of 10 experimental treatments from 19 to 21 d of age. Nine diets were formulated to evaluate 5 corn inclusion concentrations (15, 30, 45, 60, or 75%) and 2 Ca feeding strategies (fixed at 0.35% or 1.4:1 Ca:P) after 3 DAPL (zero, 24, and 48 h). As a control for DAPL, one treatment group received the common starter diet for the duration of the experiment. Broilers consuming the control diet had higher (P < 0.001) BW gain and feed intake than broilers fed the corn titration diets. Apparent ileal P digestibility of the control diet was affected (P = 0.038) by DAPL. For diets formulated with a 1.4:1 Ca:P ratio, negative linear effects (P < 0.05) on AIPD and AIIP6H were observed with increasing corn. Conversely, for diets formulated with 0.35% Ca, positive linear effects (P < 0.05) were measured for AIPD after a 48 DAPL while no linear or quadratic effects (P > 0.05) were measured for AIPD or AIIP6H for other DAPL. Broilers fed diets formulated with 1.4:1 Ca:P had variable (P < 0.05) true ileal P digestibility (TIPD; 32.2, 15.1, and 35.4%) and negative endogenous P losses (EPL; −190, −499, and −262 mg/kg DM intake) for zero, 24, and 48 h DAPL, respectively. Conversely, TIPD values (41.2, 39.1, and 47.3%) were similar (P > 0.05) and EPL were positive (102, 197, and 154 mg/kg DM intake), regardless of DAPL, for broilers fed diets formulated with 0.35% Ca. These data demonstrated that formulating diets with a 1.4:1 Ca:P ratio affected AIPD of the titration diets, shifting the regression line and predicted negative EPL and an underestimation of TIPD.