Characterization of social behavior in a group of domestic donkeys (Equus asinus)

Although the popularity of domestic donkeys is increasing, the scientific literature on their behavior is still limited. This study investigated the social behavior of a group of 13 donkeys (10 females, 3 geldings, aged 3-13 years) stabled in an Animal Assisted Interventions facility in the North of Italy. Our first aim was to assess the distribution of donkeys’ intraspecific social behaviors during daytime and the second aim was to characterize affiliative and agonistic social interactions during peak activity times. Social behaviors were expressed more between 8 and 9 AM than the rest of daytime, mainly reflecting the expression of affiliative behavior. The latter consisted mostly of proximity (55.0% of all affiliative) and following (29.2%). In most cases affiliative behavior was expressed within preferential dyads, composed of either a mother and her offspring or two adult donkeys. This supports the idea that dyadic relationships are a predominant feature of the social organization of the species. However, dyadic interactions were not observed in the oldest sub-adults, suggesting that social preferences undergo a change around the time donkeys reach full growth. Agonistic behaviors were much less common than affiliative ones. The most expressed agonistic behavior was threat (51%), followed by displacement and bite (both 18.5%). They were less expressed by donkeys who were part of an affiliative pair, suggesting that limited expression of agonistic behavior is associated with an actual change in social preferences, not a mere consequence of fewer occasions of conflict over resources. While the study has limitations, the results provide insight into the social behavior of domestic donkeys which could represent a starting point for further research as well as relevant information for donkeys farming

Temperature and humidity index (THI) affects salivary cortisol (HC) and dehydroepiandrosterone (DHEA) concentrations in growing bulls following stress generated by performance test procedures

The hypothalamus-pituitary–adrenal axis response to a challenge was proposed for genetic selection of robust and resilient animals. As ACTH (adrenocorticotropic hormone) test and hormone measurements in blood may result impractical, it may be useful to measure salivary hormones in response to natural stressors, after an accurate biological validation, to control factors that could contribute to the response. We evaluated whether animal handling during performance test affects salivary HC and DHEA secretion and could be used for selection. We tested the effects of habituation to repeated handling and THI as putative bias. Bull calves (N = 273) undergoing performance test were sampled at 8–9 and 11–13 months (N = 101), 8–9 months (N = 131), or 11–13 months (N = 41). On each test day (D0), calves were isolated, conducted to a squeeze chute and immobilized for 6 min. Saliva samples were collected in the morning after feed administration (T0), and after 6 min immobilization in the squeeze chute (T1) for HC and DHEA measurement. Environmental temperature and relative humidity were recorded every hour from 1:00 h to 24:00 h during the 6 days before the performance test and on D0. Salivary HC and DHEA concentrations were higher in T1 (p < 0.01), although a clear individual positive response to handling could be observed in less than 10% of subjects. The mixed model revealed: (i) HC and HC/DHEA were higher in Young bulls (p < 0.05). (ii) The time of T0 sample collection significantly affected DHEA (p < 0.01) and HC/DHEA (p < 0.05). (iii) THI affected both steroids (p < 0.001) but not HC/DHEA. Spearman correlations suggested that THI weakly affected salivary HC at T0 only (ρ = 0.150, p < 0.01), while moderate statistically significant correlations were found between DHEA and THI at T0 (ρ = 0.316, p < 0.001), and T1 (ρ = 0.353, p < 0.001). Salivary HC and DHEA in response to handling procedures might identify subpopulations of subjects with sensitive HPA axis. Habituation to repeated handling played a role, as the hormone response was lower in older animals. Chronic exposure to high THI had a minor effect on salivary HC visible at T0. A more intense THI effect was observed on salivary DHEA concentrations at both T0 and T1, which should be worth of further investigations

A pilot study about on-farm assessment of health and welfare in rabbits kept in different housing systems

This pilot study tested an on-farm protocol based on resource, management, and animal-based measures to evaluate the on-farm health and welfare of rabbits kept in four different housing systems. In detail, the four housing systems were (1) standard breeding cages for reproducing does (3,300 cm2) with their litters associated with bicellular cages for growing rabbits (1,200 cm2); (2) dual-purpose cages for both reproducing does and growing rabbits (3,655 cm2); (3) enriched cages (4,739 cm2) for both reproducing does and growing rabbits equipped with a wire-mesh elevated platform (1,015 cm2); (4) parks (30,977 cm2) made up of four modules (7,744 cm2 each) joined by removing the wire net walls between them with growing rabbits kept in collective parks and reproducing does individually in the single modules. A total of 12 commercial farms (three farms/four housing systems) were visited during three seasons (summer, autumn, and winter) on two occasions each: (1) a pre-weaning visit for recordings on reproducing does and litters and (2) a pre-slaughtering visit for recordings on growing rabbits. At the pre-weaning visit, the prevalence of health concerns did not differ among does and litters kept in the different housing systems. At the pre-slaughtering visit, a higher prevalence of dermatomycosis was found in farms with dual-purpose cages and parks. Overall, taking into account the limitations due to the small sample size per housing system and the field conditions, the on-farm assessment tested in the present pilot study did not highlight major differences in the welfare and health of reproducing does and their kits as well as of growing rabbits in farms using different housing systems, which need to be confirmed on a large number of farms. The study also outlined the role of several management and environmental factors changing from one farm to another, which stresses the troubles of accounting for on-farm rabbit welfare and health exclusively to the housing system.info:eu-repo/semantics/publishedVersio

Genetic Analysis of the Fatty Acid Profile in Gilthead Seabream (Sparus aurata L.).

The gilthead seabream is one of the most valuable species in the Mediterranean basin both for fisheries and aquaculture. Marine fish, such as gilthead seabream, are a source of n3 polyunsaturated fatty acids, highly appreciated for human food owing to their benefits on the cardiovascular and immune systems. The aim of the present study was to estimate heritability for fatty acid (FA) profile in fillet gilthead seabream to be considered as a strategy of a selective breeding program. Total of 399 fish, from a broodstock Mediterranean Sea, were analysed for growth, flesh composition and FA profile. Heritabilities for growth traits, and flesh composition (fat, protein, and moisture content) were medium. Heritability was moderate for 14:0, 16:0 and 18:1n9 and for sum of monounsaturated FA and n6/n3 ratio, and it was low for 20:1n11 and 22:6n3 and the ratio unsaturated/saturated FA. Breeding programs in gilthead seabream usually include growth as the first criterion in the selection process of the fish. However, other quality traits, such as fillet fat content and its fatty acids profile should be considered, since they are very important traits for the consumer, from a nutritional point of view and the benefits for the health.Versión del edito

BENESSERE NEI SISTEMI ACQUATICI: DALLE CONDIZIONI AMBIENTALI ALLE NANOTECNOLOGIE PER LA SOMMINISTRAZIONE DI PRINCIPI ATTIVI

Il benessere degli animali allevati è l'argomento principale di molti progetti di ricerca, anche se con particolare riferimento a quelli terrestri. Tuttavia, anche quelli acquatici meritano di essere considerati, ed in particolare i pesci. L'acquacoltura, infatti, è un'industria in rapida crescita, poiché l’uomo consuma una grande varietà di pesce come fonte essenziale di proteine e acidi grassi polinsaturi. Tra i diversi aspetti che influenzano il benessere dei pesci in allevamento, la dieta gioca un ruolo fondamentale: infatti, un'alimentazione squilibrata incide negativamente sulla loro salute. Inoltre, una qualità dell’acqua non ottimale e alcune pratiche comuni, come il trasporto, sono note condizioni di stress. Il primo contributo della presente tesi confronta gli effetti di un’alimentazione biologica rispetto ad una convenzionale sulle performance di crescita e sul benessere del branzino europeo. Attraverso un’analisi immunoistochimica e biomolecolare, sono stati valutati i fattori di crescita insulino-simili ed i marcatori di stress ossidativo e di contaminazione ambientale. Sebbene la dieta convenzionale abbia dato i migliori risultati in termini di produzione, anche i gruppi alimentati con quella biologica hanno mostrato una crescita positiva nel tempo e, soprattutto, non sono stati osservati effetti negativi sulla salute dei pesci. Il secondo contributo valuta la crescita e la risposta allo stress di giovanili di orata esposti a diversi fattori stressanti (variazioni di temperatura, salinità e ammoniaca), attraverso un approccio multidisciplinare che include le tecniche radioimmunologica, molecolare e immunoistochimica. I risultati hanno rivelato che tutti i fattori di stress testati hanno avuto un impatto sulla crescita e sulla salute dei pesci, in particolare l'esposizione a temperatura e a livelli di ammoniaca elevati, mentre la salinità ha avuto un effetto minore dal momento che questa specie è in grado di affrontare in modo efficiente variazioni estreme della salinità ambientale. Il terzo contributo riguarda la risposta allo stress da trasporto di giovanili di ombrina boccadoro. Sono stati misurati i livelli di cortisolo e di espressione del recettore dei glucocorticoidi e dei marcatori dello stress ossidativo. I risultati hanno dimostrato che i pesci subiscono uno stress durante l’operazione di carico, recuperando alla fine del trasporto, pur senza tornare ai livelli basali. L'acquacoltura è un importante settore economico a livello mondiale che si trova a fronteggiare una continua minaccia rappresentata dalle infezioni batteriche. Per proteggere le specie allevate è necessario ricorrere al massiccio impiego di antibiotici. L’utilizzo di nanoparticelle e lo sviluppo di nuovi nanoantibiotici rappresentano una soluzione per ridurne le quantità. L’ultimo contributo dimostra come la flumechina (FLU) nano-immobilizzata su nanoparticelle di ossido di ferro (SAMN@FLU) mostri una buona stabilità colloidale, recuperabilità mediante l'applicazione di un campo magnetico ed efficacia in vitro contro Aeromonas veronii. Inoltre l'effetto terapeutico di SAMN@FLU è stato testato su un organismo acquatico modello, Daphnia magna, che ha mostrato un'elevata tollerabilità al complesso testato. Infine, l’ultimo capitolo indaga più approfonditamente l'osservata efficacia antimicrobica del complesso. In via preliminare, dafnidi di D. magna sono stati esposti ad un'infezione batterica controllata e l’azione antimicrobica del complesso SAMN@FLU è stata confrontata con quella dell'antibiotico libero. In conclusione, la seguente tesi di dottorato considera come migliorare il benessere degli animali acquatici, a partire dalla valutazione della crescita e dello stress dei pesci in risposta a cambiamenti nelle condizioni ambientali fino al potenziale uso di un nuovo nanomateriale per la somministrazione di antibiotici in specie di interesse per l’acquacoltura.Farmed animal welfare is the chief topic of many research projects, even if with a focus on terrestrial species. Nonetheless, even the aquatic ones deserve to be considered and especially fish. Aquaculture, in fact, is a globally growing industry, since a large variety of fish is consumed as an essential source of protein and healthy lipids for human nutrition. Among the different aspects that alter farmed fish welfare, diet plays a critical role: an unbalanced nutrition may indeed severely affect fish health. In addition, non-optimal water quality and common aquaculture practices, such as transportation, are also well-known stressful conditions. The first contribution of this Ph.D. thesis compares the effects of organic vs conventional feeding on the growing performances and welfare of European sea bass. Insulin-like growth factors and oxidative stress and contaminant markers were evaluated through immunohistochemical and biomolecular analyses. Although conventional diet gave the best results in terms of production, groups fed with the organic one also showed a positive growth trend and importantly no negative effects on fish welfare were observed. The second contribution evaluates growth and stress response of gilthead seabream juveniles exposed to different stressors (temperature, salinity, ammonia content), using a multidisciplinary approach, which included radioimmunological, molecular and immunohistochemical techniques. Results revealed that all the tested stressors had an impact on fish growth and health, particularly thermic and chemical exposure, whereas salinity had a minor effect since this species can efficiently face with extreme variations in environmental salinity. The third contribution assesses meagre juveniles’ response due to transport stress. Cortisol levels, glucocorticoid receptor and oxidative stress markers’ expression have been evaluated. Results revealed that fish were stressed during loading, recovering at the end of the transport, even if without returning to basal levels. Aquaculture is an important economic sector worldwide facing an ongoing threat from infectious diseases. To overcome the disadvantages of the widespread use of antibiotics, the application of nanoparticles and the development of new nanoantibiotics represent a salution to reduce their quantitites. The last contribution demonstrates how flumequine (FLU) nano-immobilized on iron oxide nanoparticles (SAMN@FLU) showed good colloidal stability, recoverability by the application of a magnetic field and in vitro efficacy against Aeromonas veronii. Moreover, as a first step for an in vivo trial, the therapeutic effect of SAMN@FLU was tested on a model aquatic organism, Daphnia magna, which showed high tolerability to the tested complex. Finally, a further chapter investigates in depth the observed antimicrobial efficacy of the SAMN@FLU complex. D. magna daphnids were exposed to a controlled bacterial infection and the antimicrobial activity of the SAMN@FLU complex was compared with that of the free antibiotic. Since experiments are still in progress, only preliminary results are reported in this last chapter. In conclusion, the following Ph.D. thesis provides useful tools to improve aquatic animal life conditions, from the assessment of fish growth and stress in response to changes in environmental conditions to the encouraging use of an innovative nanocarrier for antibiotic administration in reared fish species

Growth performance and gut response of broiler chickens fed diets supplemented with grape (Vitis vinifera L.) seed extract

To evaluate the effects of the dietary supplementation with a grape seeds extract (GSE) on growth performance, gut morphology and immune response, and meat quality, 800 chickens (8 pens/group) were fed a control diet or the same diet added with 0.1%, 0.2%, or 0.4% GSE from hatching to 42 d of age. Growth performance did not differ among dietary treatments: final live weight averaged at 3,179 g, which corresponded to a daily growth rate of 76.1 g/d; feed intake averaged 113 g/d, for a feed conversion ratio at 1.49. On average of samplings at 14 d and 28 d of age, the density of CD45þ cells in the jejunal mucosa was higher (2,497 vs. 1,931 cells/ 10,000 lm2; p &lt; .001) in chickens fed diet 0.2% GSE compared to chickens fed the other diets; jejunum villi height tended to be lower in chickens fed diet 0.2% GSE compared to those fed the other diets (965 lm vs. 1,054 lm; p ¼ .07). Slaughter results and carcase traits, occurrence of myopathies at breast and meat quality after 24 h or 11 d of refrigerated storage were not affected by GSE inclusion or level. Under the conditions of the present study, no relevant effect of the dietary inclusion of GSE was observed on performance and health, but a pro-inflammatory immune response at the level of jejunum, based on which a positive response of chickens fed GSE can be expected under challenging conditions

Growth and stress evaluation in juvenile diploid and triploid Atlantic salmon (Salmo salar) during smoltification.

Growth and stress evaluation in juvenile diploid and triploid Atlantic salmon (Salmo salar) during smoltification

Stress response in meagre (Argyrosomus regius) juveniles: comparison between manual and mechanical grading.

Stress response in meagre (Argyrosomus regius) juveniles: comparison between manual and mechanical grading