Goat mammary gland metabolism: An integrated Omics analysis to unravel seasonal weight loss tolerance.

Seasonal weight loss (SWL), is a major limitation to animal production. In the Canary Islands, there are two dairy goat breeds with different levels of tolerance to SWL: Majorera (tolerant) and Palmera (susceptible). Our team has studied the response of these breeds to SWL using different Omics tools. The objective of this study was to integrate such results in a data driven approach and using dedicated tools, namely the DIABLO method. The outputs of our analysis mainly separate unrestricted from restricted goats. Metabolites behave as "hub" molecules, grouping interactions with several genes and proteins. Unrestricted goats upregulated protein synthesis, along with arginine catabolism and adipogenesis pathways, which are related with higher anabolic rates and a larger proportion of secretory tissue, in agreement with their higher milk production. Contrarily, restricted goats seemingly increased the synthesis of acetyl-CoA through serine and acetate conversion into pyruvate. This may have occurred to increase fatty acid synthesis and/or to use them as an energy source in detriment to glucose, which was more available in the diet of unrestricted goats. Lastly, restricted Palmera upregulated the expression of PEBP4 and GPD1 genes compared to all other groups, which might support their use as putative biomarkers for SWL susceptibility. SIGNIFICANCE: Seasonal weight loss (SWL) is a major issue influencing animal production in the tropics and Mediterranean. By studying its impact on the mammary gland of tolerant and susceptible dairy goat breeds, using Omics, we aim at surveying the tissue for possible biomarkers that reflect these traits. In this study, data integration of three Omics (transcriptomics, proteomics and metabolomics) was performed using bioinformatic tools, to relate putative biomarkers and evaluate all three levels of information; in a novel approach. This information can enhance selection programs, lowering the impact of SWL on food production systems.

Enhanced ileum function in weaned piglets via Laminaria digitata and alginate lyase dietary inclusion: A combined proteomics and metabolomics analysis.

Laminaria digitata, a brown seaweed with prebiotic properties, can potentially enhance the resilience of weaned piglets to nutritional distress. However, their cell wall polysaccharides elude digestion by monogastric animals' endogenous enzymes. In vitro studies suggest alginate lyase's ability to degrade such polysaccharides. This study aimed to assess the impact of a 10% dietary inclusion of L. digitata and alginate lyase supplementation on the ileum proteome and metabolome, adopting a hypothesis-generating approach. Findings indicated that control piglets escalated glucose usage as an enteric energy source, as evidenced by the increased abundance of PKLR and PCK2 proteins and decreased tissue glucose concentration. Additionally, the inclusion of seaweed fostered a rise in proteins linked to enhanced enterocyte structural integrity (ACTBL2, CRMP1, FLII, EML2 and MYLK), elevated peptidase activity (NAALADL1 and CAPNS1), and heightened anti-inflammatory activity (C3), underscoring improved intestinal function. In addition, seaweed-fed piglets showed a reduced abundance of proteins related to apoptosis (ERN2) and proteolysis (DPP4). Alginate lyase supplementation appeared to amplify the initial effects of seaweed-only feeding, by boosting the number of differential proteins within the same pathways. This amplification is potentially due to increased intracellular nutrient availability, making a compelling case for further exploration of this dietary approach. SIGNIFICANCE: Pig production used to rely heavily on antibiotics and zinc oxide to deal with post-weaning stress in a cost-effective way. Their negative repercussions on public health and the environment have motivated heavy restrictions, and a consequent search for alternative feed ingredients/supplements. One of such alternatives is Laminaria digitata, a brown seaweed whose prebiotic components that can help weaned piglets deal with nutritional stress, by improving their gut health and immune status. However, their recalcitrant cell walls have antinutritional properties, for which alginate lyase supplementation is a possible solution. By evaluating ileal metabolism as influenced by dietary seaweed and enzyme supplementation, we aim at discovering how the weaned piglet adapts to them and what are their effects on this important segment of the digestive system.

Muscle mineral profile of water buffaloes (Bubalus bubalis) reared in different production systems of the Brazilian Eastern Amazon.

Healthy food must have an adequate balance of macroelements, such as calcium or phosphorus and, microelements, such as iron, copper. This study aimed to evaluate the influence of three extensive systems, during the dry and rainy seasons, and an intensive (feedlot) system in the Eastern Amazon, on the muscle mineral profile of water buffaloes. In total, 12 male buffaloes, aged between 24 and 36 months, slaughtered in commercial slaughterhouses, were used in each of the systems considered: Marajó island, Santarém, Nova Timboteua, and a feedlot. Approximately 5 g of muscle was collected, stored, and frozen, until freeze-dried. The samples were analyzed for the mineral profile using inductively coupled plasma-optical emission spectrometry (ICP-OES). There were significant differences (P < 0.05) for concentrations of sodium (Na), magnesium (Mg), phosphorus (P), sulfur (S), copper (Cu), zinc (Zn), and iron (Fe). Extensive and intensive systems showed significant differences (P < 0.05) for Na, Ca, S, Cu, and Fe concentrations. The season also influenced (P < 0.05) K, Ca, P, S, Zn, and Fe concentrations. The location and season of the year had a significant interaction (P < 0.05) for K, Mg, P, Zn, and Fe concentrations. The study showed that the different Amazonian production systems and the year season influenced the levels of minerals present in buffalo muscle. The values obtained were, in general, higher in extensive production systems, and Marajó Island stood out with higher mineral values in the dry season. Therefore, the meat from animals reared in these systems is a good mineral source for daily human needs.

Mineral Content of Liver of Buffaloes (Bubalus bubalis) Reared in Different Ecosystems in the Eastern Amazon.

This study aimed to evaluate the influence of different production ecosystems, three in native and cultivated pastures (extensive), at two seasons of the year (dry and rainy), and one in confinement (intensive) in the Eastern Amazon, on the mineral content of buffalo liver raised on these ecosystems. Twelve male buffalo (n = 12), aged between 24 and 36 months, slaughtered in commercial slaughterhouses, were used in each of the ecosystems considered: Marajó; Lower Amazon; Cultivated Pasture, and in confinement system, Pará, Brazil. Approximately 5 g of liver was collected, stored and frozen until lyophilization. Samples were analyzed for mineral content based on inductively coupled plasma optical emission spectrometry (ICPOES) readings. The relationship between extensive ecosystems and an intensive production system (p < 0.05) in the values of potassium (K), iron (Fe), copper (Cu), manganese (Mn) and barium (Ba) was evaluated. The different ecosystems studied influenced (p < 0.05) the mineral values found in the liver of buffaloes raised in the ecosystems, for sodium (Na), K, calcium (Ca), magnesium (Mg), sulfur (S), copper (Cu), iron (Fe), manganese (Mn) and barium (Ba). The period of the year interacted with the values of Na, K, S and Cu; however, an interaction of local vs. period of the yer was observed for the values of K, Mg, P, S and Cu. It can be concluded that the buffalo liver is an excellent source of minerals and can be included in the human diet and that the ecosystem the animals are raised influences its content.

Integrated Omics analysis of pig muscle metabolism under the effects of dietary Chlorella vulgaris and exogenous enzymes.

Monogastric feeding is dependent on costly conventional feedstuffs. Microalgae such as Chlorella vulgaris are a sustainable alternative; however, its recalcitrant cell wall hinders monogastric digestion. Carbohydrate Active Enzyme (CAZyme) supplementation is a possible solution. The objective of this work was to evaluate the effect of 5% dietary C. vulgaris (CV) and enzymatic supplementation (CV + R-Rovabio® Excel AP; CV + M-four CAZyme mix) on muscle transcriptome and proteome of finishing pigs, in an integrated approach. Control pigs increased the abundance of contractile apparatus (MYH1, MYH2, MYH4) and energy metabolism (CKMT1, NDUFS3) proteins, demonstrating increased nutrient availability. They had increased expression of SCD, characteristic of increased glucose availability, via the activation of SREBP-1c and ChREBP. CV and CV + R pigs upregulated proteolytic and apoptotic genes (BAX, DDA1), whilst increasing the abundance of glucose (UQCRFS1) and fatty acid catabolism (ACADS) proteins. CV + R pigs upregulated ACOT8 and SIRT3 genes as a response to reduced nutrient availability, maintaining energy homeostasis. The cell wall specific CAZyme mix, CV + M, was able to comparatively reduce Omics alterations in the muscle, thereby reducing endogenous nutrient catabolism compared to the CV + R and CV.

Quality Traits and Nutritional Value of Pork and Poultry Meat from Animals Fed with Seaweeds.

Seaweeds have caught the attention of the scientific community in recent years. Their production can mitigate the negative impact of anthropogenic activity and their use in animal nutrition reduces the dependency on conventional crops such as maize and soybean meal. In the context of monogastric animals, novel approaches have made it possible to optimise their use in feed, namely polysaccharide extraction, biomass fermentation, enzymatic processing, and feed supplementation with carbohydrate-active enzymes (CAZymes). Their bioactive properties make them putative candidates as feed ingredients that enhance meat quality traits, such as lipid oxidation, shelf-life, and meat colour. Indeed, they are excellent sources of essential amino acids, polyunsaturated fatty acids, minerals, and pigments that can be transferred to the meat of monogastric animals. However, their nutritional composition is highly variable, depending on species, harvesting region, local pollution, and harvesting season, among other factors. In this review, we assess the current use and challenges of using seaweeds in pig and poultry diets, envisaging to improve meat quality and its nutritional value.

Water buffalo production in the Brazilian Amazon Basin: a review.

The Brazilian Amazon has witnessed, in the last decades, an increase in the water buffalo (Bubalus bubalis) inventory, with interesting productivity results. As the Brazilian Amazon contains the main water buffalo population in the Americas, the aim of this work is to review its most relevant production systems and some peculiarities about meat and milk production in this territory. The opening section describes the Amazon Basin, the most common water buffalo breeds, a brief history of the local livestock farming beginning in 1644. Also, it presents how water buffaloes gradually replaced bovine herds, especially where the latter had a lower productive performance. The use of extensive or more intensified models is pointed out and the ecosystems in which buffaloes are raised are detailed since native or cultivated pastures can be used in floodplains or drylands. Buffalo raising is favored in the Amazon due to the climate, soil, genetic variability of forages, animal adaptability, and physical space. Thus, it is clear that buffaloes have a high potential for meat and milk production and are an alternative in the use of altered areas of the Amazon; and, in the recent past, the low profitability of buffalo farming in traditional production systems in the Amazon was the reason which made this activity economically unattractive. Most recent technologies as outdoor confinements and silvopastoral systems are pointed out as more suitable regarding land-use policies, and buffalo farming for meat and milk production fits perfectly in this context, with productivity and beneficial socioeconomic.

Understanding seasonal weight loss tolerance in dairy goats: a transcriptomics approach.

BACKGROUND: Seasonal weight loss (SWL) is a very important limitation to the production of ruminants in the Mediterranean and Tropical regions. In these areas, long dry seasons lead to poor pastures with low nutritional value. During the dry season, ruminants, particularly those raised in extensive production systems, lose around 30% of their body weight. Seasonal weight loss has important consequences on animal productive performance and health. In this study, RNA sequencing was used to characterize feed restriction effects in dairy goat of 2 breeds with different SWL tolerance: Majorera (tolerant) and Palmera (susceptible). Nine Majorera and ten Palmera goats were randomly distributed in a control and a restricted group: Majorera Control (adequately fed; MC; n = 4), Palmera Control (adequately fed; PC; n = 6), Majorera Restricted (feed restricted; ME; n = 5) and Palmera Restricted (feed restricted; PE; n = 4). On day 22 of the trial, mammary gland biopsies were collected for transcriptomics analysis. RESULTS: From these samples, 24,260 unique transcripts were identified. From those, 82 transcripts were differentially expressed between MC and ME, 99 between PC and PE, twelve between both control groups and twenty-nine between both restricted groups. CONCLUSIONS: Feed restriction affected several biochemical pathways in both breeds such as: carbohydrate and lipid transport; intracellular trafficking, RNA processing and signal transduction. This research also highlights the importance or involvement of the genes in tolerance (ENPP1, S-LZ, MT2A and GPNB) and susceptibility (GPD1, CTPS1, ELOVL6 and NR4A1) to SWL with respectively higher expression in the Majorera restriced group and the Palmera restricted group in comparison to the control groups. In addition, results from the study may be extrapolated to other dairy ruminant species.

Mineral profiling of muscle and hepatic tissues of Australian Merino, Damara and Dorper lambs: Effect of weight loss.

Seasonal weight loss (SWL) is a major constraint to extensive animal production systems. The Australian sheep production is based on merino sheep, a European breed not tolerant to SWL. Tolerant alternative breeds such as the fat-tailed Damara and the Dorper have been increasingly used in Australia and elsewhere, due to their robustness. The aim of this study was to understand the mineral profile of muscle and liver tissues of Australian Merino, Damara and Dorper, when subjected to SWL in order to understand SWL-tolerance physiology. Twenty-four lambs were divided randomly between growing (control) and nutritionally restricted groups for each breed. The trial lasted 42 days. Animals were weighed bi-weekly and at the end of the trial, lambs were slaughtered. Liver and muscle samples were taken immediately after slaughter. Mineral assessment was carried out using inductively coupled plasma-optical emission spectrometry. Analysis of variance showed mineral concentrations were generally increased in the muscle of restricted animals, mainly because of fat tissue mobilization. An increase in Zn and Fe concentrations indicates an increase of enzymatic activity in the liver of restricted sheep as well as differential abundance of Fe-containing proteins. High concentrations of Cu in the liver of Dorper indicate higher ability to accumulate this element, even under SWL.

NMR-metabolomics profiling of mammary gland secretory tissue and milk serum in two goat breeds with different levels of tolerance to seasonal weight loss.

Goats are of special importance in the Mediterranean and tropical regions for producing a variety of dairy products. The scarcity of pastures during the dry season leads to seasonal weight loss (SWL), which affects milk production. In this work, we studied the effect of feed-restriction on two dairy goat breeds, with different tolerance levels to SWL: the Majorera breed (tolerant) and the Palmera breed (susceptible). Nuclear magnetic resonance (NMR) was used to compare the metabolome of an aqueous fraction of the mammary gland and milk serum from both breeds. Goats in mid-lactation were divided by breed, and each in two feed-regime groups: the control group and the restricted-fed group (to achieve 15-20% reduction of body weight at the end of the experiment). Milk and mammary gland samples were collected at the end of the experimental period (23rd day). (1)H NMR spectra were collected from the aqueous extract of the mammary gland biopsies and the milk serum. Profiling analysis has led to the identification of 46 metabolites in the aqueous extract of the mammary gland. Lactose, glutamate, glycine and lactate were found to be the most abundant. Analysis of milk serum allowed the identification of 50 metabolites, the most abundant being lactose, citrate and creatine. Significant differences were observed, in mammary gland biopsies and milk serum, between control and restricted-fed groups in both breeds, albeit with no differences between the breeds. Variations seem to be related to metabolism adaptation to the low-energy diet and are indicative of breed-specific microflora. Milk serum showed more metabolites varying between control and restricted groups, than the mammary gland. The Majorera breed also showed more variations than the Palmera breed in milk samples, which could be an indication of a prompt adaptation to SWL by the Majorera breed.

Sequence Analysis of Bitter Taste Receptor Gene Repertoires in Different Ruminant Species.

Bitter taste has been extensively studied in mammalian species and is associated with sensitivity to toxins and with food choices that avoid dangerous substances in the diet. At the molecular level, bitter compounds are sensed by bitter taste receptor proteins (T2R) present at the surface of taste receptor cells in the gustatory papillae. Our work aims at exploring the phylogenetic relationships of T2R gene sequences within different ruminant species. To accomplish this goal, we gathered a collection of ruminant species with different feeding behaviors and for which no genome data is available: American bison, chamois, elk, European bison, fallow deer, goat, moose, mouflon, muskox, red deer, reindeer and white tailed deer. The herbivores chosen for this study belong to different taxonomic families and habitats, and hence, exhibit distinct foraging behaviors and diet preferences. We describe the first partial repertoires of T2R gene sequences for these species obtained by direct sequencing. We then consider the homology and evolutionary history of these receptors within this ruminant group, and whether it relates to feeding type classification, using MEGA software. Our results suggest that phylogenetic proximity of T2R genes corresponds more to the traditional taxonomic groups of the species rather than reflecting a categorization by feeding strategy.

Rabbit muscle proteomics: a great leap forward.

The rabbit is an important species as both a production animal and as a model organism in physiology, pharmaceutical, and numerous other studies. Similar to other species, the rabbit skeletal muscle proteome has been characterized, first using 2DE mapping and more recently using high-throughput shotgun proteomics. This article is a commentary on "Shotgun proteomics analysis of the sarcoplasmic reticulum preparations from rabbit skeletal muscle" (Z. Liu et al., Proteomics, 2013, 13, 2335-2338). Herein, we present the reasons why the manuscript is of high relevance to three major fields: farm animal, rabbit, and muscle/meat proteomics.

Muscle and meat: new horizons and applications for proteomics on a farm to fork perspective.

Meat consumption is an important part of human diet with strong implications in health, economy and culture worldwide. Meat is a proteinaceous product and therefore proteomics holds a considerable value to the study of the protein events underlying meat production and processing. In this article we will review this subject in an integrated "farm to fork" perspective, i.e. focusing on all the major levels of the meat producing chain: farm, abattoir and transformation industry. We will focus on the use, importance and applications of proteomics, providing clear examples of the most relevant studies in the field. A special attention will be given to meat production, as well as quality control. In the latter, a particular emphasis will be given to microbial safety and the detection of frauds.

Pig proteomics: a review of a species in the crossroad between biomedical and food sciences.

The pig (Sus scrofa) is one of the most important animal species used for meat production worldwide, playing a fundamental role in numerous cultures from Southern Europe to the Pacific Islands. Additionally, it is broadly used as an experimental animal for several purposes, from physiological studies to drug testing and surgical training. Proteomics studies have covered both physiological and biomedical application studies of pig to a much greater extent than for any other farm animal. Despite this fact, no review seems to be available on the application of proteomics to production aspects in pig. The aim of this article is to provide a review on such applications of proteomics to the pig species. The article is divided in three parts. The first is dedicated to productive characterization and includes aspects related to reproduction and meat science. The second concerns the management of health and disease in production. Finally, the third part concerns the use of the pig as a model organism in biomedical research.

Tick-borne diseases in cattle: applications of proteomics to develop new generation vaccines.

Tick-borne diseases (TBDs) affect 80% of the world's cattle population, hampering livestock production throughout the world. Livestock industry is important to rural populations not only as food supply, but also as a source of income. Tick control is usually achieved by using acaricides which are expensive, deleterious to the environment and can induce chemical resistance of vectors; the development of more effective and sustainable control methods is therefore required. Theileriosis, babesiosis, anaplasmosis and heartwater are the most important TBDs in cattle. Immunization strategies are currently available but with variable efficacy. To develop a new generation of vaccines which are more efficient, cheaper and safer, it is first necessary to better understand the mechanisms by which these parasites are transmitted, multiply and cause disease; this becomes especially difficult due to their complex life cycles, in vitro culture conditions and the lack of genetic tools to manipulate them. Proteomics and other complementary post-genomic tools such as transcriptomics and metabolomics in a systems biology context are becoming key tools to increase knowledge on the biology of infectious diseases. Herein, we present an overview of the so called "Omics" studies currently available on these tick-borne pathogens, giving emphasis to proteomics and how it may help to discover new vaccine candidates to control TBDs.

Proteomic analyses of Ehrlichia ruminantium highlight differential expression of MAP1-family proteins.

The Rickettsiales Ehrlichia ruminantium (ER) is the causative agent of heartwater, a fatal tick-borne disease of livestock in sub-Saharan Africa and in the Caribbean, posing strong economical constraints to livestock production. In an attempt to identify the most prominent proteins expressed by this bacterium, especially those encoded by the major antigenic protein 1 (map1) multigene family, a proteome map of ER cultivated in endothelial cells was constructed by using two dimensional gel electrophoresis combined with mass spectrometry. Among the sixty-four spots detected, we could identify only four proteins from the MAP1-family; the other proteins detected were mainly related to energy, amino acid and general metabolism (26%), to protein turnover, chaperones and survival (21%) and to information processes (14%) or classified as hypothetical proteins (23%). Additional studies on MAP1-family protein using immunochemical labeling also revealed that these proteins are differentially expressed along the bacterium life cycle, presenting different structural organization. Interestingly, when infectious elementary bodies (EBs) are released from host cells, MAP1 appears to be organized in SDS and heat-resistant dimers and trimers stabilized by disulfide bridges. Overall, the results presented herein not only reveal the first partial proteome map of ER but provide new insights on the expression ER MAP1-family proteins in host endothelial cells.

First identification of tannin-binding proteins in saliva of Papio hamadryas using MS/MS mass spectrometry.

Hamadryas baboons possess salivary proline-rich proteins (PRP), as indicated by the presence of pink-staining protein bands using 1D SDS gel electrophoresis and Coomassie R250 staining. The ability of these protein bands to interact with tannic acid was further examined. In a tannin-binding assay using 5 µg tannic acid mixed with hamadryas whole saliva, we recently found four distinct protein bands of apparently 72, 55, 20, and 15 kDa that were precipitated during the experiments. In this work, we were able to identify these protein bands in a follow-up analysis using MS/MS mass spectrometry after excising such bands out of air-dried gels. Albumin and α-amylase were present in the tannic acid-protein complexes, with albumin already known to nonspecifically interact with a great diversity of chemical compounds. More interesting, we also identified a basic PRP and a cystatin precursor protein. This was the first successful attempt to identify a PRP from precipitated tannin-protein complexes in hamadryas baboons using MS/MS mass spectrometry. On the other hand, the role of cystatins in tannin binding is not yet well understood. However, there are recent reports on cystatin expression in saliva of rats responding to astringent dietary compounds. In conclusion, the follow-up data on tannin-binding proteins present in salivary secretions from hamadryas baboons adds important knowledge to primate physiology and feeding ecology, in order to shed light on the establishment and development of food adaptations in primates. It also demonstrates that tannin binding is characteristic for PRP, but might not be restricted to this particular group of proteins in primate species.

Differential protein expression in two bivalve species; Mytilus galloprovincialis and Corbicula fluminea; exposed to Cylindrospermopsis raciborskii cells.

The cyanobacteria Cylindrospermopsis raciborskii is considered a threat to aquatic organisms due to the production of the toxin cylindrospermopsin (CYN). Despite the numerous reports evidencing the toxic effects of C. raciborskii cells and CYN in different species, not much is known regarding the toxicity mechanisms associated with this toxin and the cyanobacteria. In this work, a proteomics approach based in the two-dimensional gel electrophoresis and mass spectrometry was used to study the effects of the exposure of two bivalve species, Mytilus galloprovincialis and Corbicula fluminea, to CYN producing (CYN+) and non-producing (CYN-) C. raciborskii cells. Additionally the activities of glutathione S-transferase (GST) and glutathione peroxidase (GPx) were determined. Alterations in actin and tubulin isoforms were detected in gills of both bivalve species and digestive gland of M. galloprovincialis when exposed to CYN- and CYN+ cells. Moreover, GST and GPx activities changed in gills and digestive tract of bivalves exposed to both C. raciborskii freeze dried cells, in comparison to control animals exposed to the green alga Chlorella vulgaris. These results suggest the induction of physiological stress and tissue injury in bivalves by C. raciborskii. This condition is supported by the changes observed in GPx and GST activities which indicate alterations in the oxidative stress defense mechanisms. The results also evidence the capacity of CYN non-producing C. raciborskii to induce biochemical responses and therefore its toxicity potential to bivalves. The heat shock protein 60 (HSP60), extrapallial (EP) fluid protein and triosephosphate isomerase homologous proteins from gills of M. galloprovincialis were down-regulated specifically with the presence of CYN+ C. raciborskii cells. The presence of CYN may lead to additional toxic effects in M. galloprovincialis. This work demonstrates that proteomics is a powerful approach to characterize the biochemical effects of C. raciborskii and to investigate the physiological condition of the exposed organisms.

The effect of the Naked Neck genotype (Nana), feeding and outdoor rearing on growth and carcass characteristics of free range broilers in a hot climate.

Alternative poultry production with special reference to free range broilers has increased significantly since the nineties in many regions of the world. Numerous factors influence the productive performance of this type of broilers: genotype (namely the use of naked neck animals), feeding and access to an outdoor area. The aim of this paper is to study the influence of each of these factors on the productive performance of free range broilers under commercial rearing conditions. A total of 3200, day old chicks of both sexes from naked neck and normally feathered genotypes were used in this trial. After a joint initiation phase, animals were divided into four different treatments with the combination of two concentrates (high vs low energy content) and management (access to outside park or not). Experiment lasted a total of 12 weeks. Live weight date was recorded weekly and a samples of animals from the trial were sacrificed at the age of 8, 10 and 12 weeks, when carcass characteristics were determined. Besides sex, the only factor that seems to affect growth characteristics was genotype as naked neck animals had poorer growth rates than normally feathered. No effect was detected on carcass yields and percentages of carcass components for any of the variables. From the data presented in this trial the practises associated with free range production are of relative inconsequence to the technical animal production parameters and can only be justified by a pressing need to differentiate these products from standard poultry products in what concerns both welfare issues and meat characteristics. The results also indicate that genetic material from alternative poultry production in Europe can be a useful option in poultry production development projects in the tropics.