Use of alternative protein sources in poultry and fish nutrition

The global increase of the world population started during the ‘60s and the most credited FAO estimates predicted that by the mid-twentieth century the human population will still grow to reach about 9 billion. Likewise, in order to satisfy the nutritional needs of both humans and livestock and pet animals, the demand of raw materials and in particular protein sources will increase. It is estimated that in the near future the production of meat will increase of 50%, and the demand of fish, milk and eggs of 75%. The most important protein sources used in animal nutrition are the soybean meal and the fish meal; however, the production of these two raw materials are linked to several environmental problems. Recently, the researchers are studying the use of innovative protein sources alternative to the soybean and fish meal presenting the best possible characteristics such as: environmental sustainability, low production costs, high nutritional value and no antinutritional factor content. The insects and the processed animal proteins (PAPs) could be suitable protein sources in poultry and fish nutrition. The present thesis includes 6 experimental trials conducted along the three years of my PhD in Italy and in Greece in order to evaluate the possible utilization of innovative and alternative protein sources in poultry and in fish species. Regarding poultry, the studies has been conducted in Italy. The first step was to investigate the in vitro crude protein digestibility of different insect meals from Tenebrio molitor and Hermetia illucens and their correlation with chemical composition traits. The results showed that chitin is the main constituent of insect body able to affect the crude protein digestibility of Tenebrio molitor and Hermetia illucens larvae meals. Based on these results two in vivo trials were carried out on the use of the insect meals in the poultry diets. The first in vivo study was carried out on 80 broilers (from 30 to 62 days of age) equally divided into two groups fed, respectively, a corn-soybean meal based diet and a diet in which Tenebrio molitor larvae meal totally replaced the soybean meal. The diets were isoproteic and isoenergetic. No differences were observed on growth parameters, physical and chemical properties of the meat between the groups. The presence of the chitin in the insect meal increased the length and the weight of the full intestine, the weight of the spleen, the production of the caecal volatile fatty acids; and it affected negatively the apparent ileal digestibility of nutrients and in particular of the proteins. In addition, broilers fed the insects had a lower albumin to globulin ratio in the blood samples than the group fed soybean meal and this suggests a better disease resistance and immune response of birds linked to the prebiotic activity of the chitin. The second in vivo study was carried out on 108 laying hens (from 24 to 45 weeks of age). Following a scheme similar to that of the previous trial, the hens were equally dived into two groups fed two isoproteic and isoenergetic diets. The control group fed a corn-soybean meal based diet and the other group fed a diet in which an Hermetia illucens larvae meal was included as total replacement of the soybean meal. The use of the insect meal did not show negative effects on the health status of the animals and on the feed conversion ratio. However, the complete replacement of soybean meal showed negative effects on the feed intake and, as a consequence, on the laying performance. The chitin content of the the Hermetia illucens diet negatively affected the ileal apparent digestibility of the nutrients and, in particular, of the proteins. The eggs quality was positively affected by the insect meal based diet, in particular the yolk resulted richer in PUFA, n-6 and n-3 and showed lower cholesterol content than the hens fed on the soybean meal based diet. The three studies on fish species were carried out in Greece. The first step was to evaluate the suitability of some processed animal proteins carrying out a preliminary in vivo digestibility trial; a control diet (with only fish meal) was compared to six isoproteic and isoenergetic diets including, respectively, poultry feather meal (FeM) alone (4 diets with 15, 25, 50 and 75% of fish meal substitution) and a mix of processed animal proteins meals (2 diets including feather meal, offal meal and blood meal (BOF) added to the diet in equal amounts to replace 50 and 75 % of the fish meal). The trial evidenced a decrease of nutrients digestibility for feather meal containing diets starting from the 15% fish meal substitution rate diet. The diets containing a mix of processed animal proteins, instead, showed better results, with the 50% fish meal substitution rate diet presenting values comparable to the control diet. A worsening of digestibility was registered, instead for the 75% substitution rate diet. After this preliminary trial two growth trials were carried out in order to evaluate the growth performance of the European sea bass fed on the only feather meal based diets (360 European sea bass juveniles) and the mix of ingredients previously described (225 juveniles European sea bass). The diets with the only inclusion of feather meal put in evidence that the only suitable diet was the 15% FM. The experimental diet with the mix of the ingredient showed promising results, because the inclusion of 50% BOF showed growth performance results comparable to the control diet

Role of Caprine Herpesvirus – 1 (CpHV-1) in the innate immuno-evasion Interferon mediate.

Caprine Herpesvirus-1 (CpHV-1) is a member of Varicellovirus genus within Herpesvirus family. CpHV-1 is the responsible of a disease that causes respiratory symptoms, balanopostitis, vulvovaginitis and abortion in adult goats. It also affects young goats with a systemic disease [1]. Type I (IFN-a/ ) and type II (IFN g) interferons, are the first weapons of the host to fight against viral infections. Type I IFNs induce the expression of more than 100 Interferon Stimulated Genes (ISGs) to establish an antiviral state that limits viral replication and dissemination. [2] Type II IFN is produced by activated immune cells and leads to the production of a different subset of ISGs via a distinct signaling pathway. Many viruses are able to subvert both type I and type II IFN-mediated antiviral responses. Herpesviruses are able to evade the IFN response by targeting different transcriptions factors of the interferon (IFN) signaling pathway [3]. There are no reports in literature about the role of CpHV-1 in IFN antagonism. Aim of the work: Herein, we describe a work to address the possible role of CpHV-1 as modulator of the innate immune response interferon mediate. Materials and methods. To investigate whether CpHV-1 interferes with type I interferon production, we performed an IFN- Beta reporter assay, using a reporter plasmid that carries the IFN-Beta promoter driving the expression of a firefly luciferase gene. A renilla-luciferase reporter plasmid was used as control. For the activation of the pathway we used the constitutively active N-terminal (2CARD) domain of RIG-I. To evaluate the potential CpHV-1-mediated inhibition of IFN a/b signaling, we performed an ISRE54 reporter assay using a construct having an ISRE54 promoter driving the expression of firefly luciferase. A renilla-luciferase reporter plasmid was used as internal control. Results. Our results show that CpHV-1 infection strongly suppressed the activation of IFN-β promoter induced by RIGI 2 CARD domain. Moreover cells mock infected and treated with type I IFN showed a significant increase in luciferase expression, as expected compared with the cells that were not treated with type I IFN and were not infected. The cells infected with CpHV-1 and treated with type I IFN showed significantly reduced luciferase expression driven by the ISRE54 promoter. These results showed that CpHV-1 is a strong inhibitor of type I Interferon production and signaling pathways. [1] Tempesta M, Pratelli A, Greco G, Martella V, Buonavoglia C, 1999. Detection of caprine herpes virus 1 in the sacral ganglia of latently infected goats by polimerasi chain reactionj J Clin Microbiol 37, 1598-99. [2] Garcia-Sastre A, Biron CA (2006) Type 1 interferons and the virus-host relationship: a lesson in detente. Science 312: 879-882. [3] Afroz S, Brownlie R, Fodje M, van Drunen Littel-van den Hurk S. VP8, the Major Tegument Protein of Bovine Herpesvirus 1, Interacts with Cellular STAT1 and Inhibits Interferon Beta Signaling. J Virol. 2016 Apr 29; 90(10): 4889-904

Fatty acid profile of lipids and caeca volatile fatty acid production of broilers fed a full fat meal from Tenebrio molitor larvae

Volatile fatty acid production (VFA) in the caeca and fatty acid profile of meat and fat depotswere investigated on 62 days old broiler equally divided in 2 groups fed with a corn-soybean(SBM) or a corn-insect meal (TML, fromTenebrio molitorlarvae) based diet from 30 days of age.The total amount of VFAs was higher (p<.01) in broilers fed TML and the same happened forall the single VFA studied in the trial. When the VFAs were expressed as percentage of totalVFAs, acetate, propionate and valerianate were higher (p<.01) in SBM group, while the propor-tion of butyrate was higher (p<.01) in broilers fed TML. The fatty acids C12:0 and C14:0 hadhigher percentages (p<.01 andp<.05, respectively) in the intramuscular fat of broilers fed TMLdiet. Regarding the FA groups (SFA, MUFA and PUFAs), only the PUFAn1 fatty acids were higher(p<.01) in the broilers fed TML diet. Insect meals can affect the microbial activity in broilercaeca and, in addition, induced very few modifications in the fatty acid profile of broiler breast

In vitro crude protein digestibility of tenebrio molitor and hermetia illucens insect meals and its correlation with chemical composition traits

The aims of this study were to evaluate the correlation between in vitro crude protein digestibility coefficients of insect meals from Tenebrio molitor (TI) and Hermetia illucens (HI) and their chemical composition traits as well as to develop regression equations able to estimate the in vitro crude protein digestibility (CPd) from proximate analysis of insect meals. Twelve samples of insect meals (6 from TM larvae, TM 1-6 and 6 from HI larvae, HI 1-6) were obtained from different producers and analysed for chemical composition and in vitro crude protein digestibility by a two-step enzymatic method (digestion with pepsin and trypsin-enriched pancreatin). For both insect meal samples, CPd was negatively correlated to ADF and chitin contents, while just for HI there was a positive correlation (P&lt;0.01) between CP percentage of the samples and CPd. For both insect meals the former variable chosen in the stepwise analysis was the chitin, explaining the 79.45% of CPd variability for Tenebrio molitor samples and the 98.30% for Hermetia illucens. In the second step, the amount of protein linked to ADF was added in the model for T. molitor and CP for H. illucens samples. The coefficients chitin is the main constituent of insect body able to affect the crude protein digestibility of Tenebrio molitor and Hermetia illucens larvae meals estimated by an in vitro enzymatic method

Effect of the housing system (free-range vs. open air cages) on growth performance, carcass and meat quality and antioxidant capacity of rabbits

Growth performances and meat quality of free-range or cage raised rabbits were compared in 36 male animals. Rabbits were raised in free-range areas (2000 cm2/head) or in open-air cages (800 cm2/head) from weaning to 99 days old. Daily weight gain and final live weight were higher (P &lt; 0.05) for the rabbits raised in cages which presented a more favourable feed conversion ratio (P &lt; 0.05) than in the free-range group. The average feed intake, liver and empty gastro-intestinal tract weights were higher (P &lt; 0.05) in the free-range group, while the interscapular fat percentage was higher (P &lt; 0.05) in the caged rabbits. Loins of free-range rabbits had higher amount of PUFA n-6 in neutral lipids (P &lt; 0.05) whereas their polar lipids were richer in PUFA n-6 and n-3 than in those of the cage group. Muscular fat of free-raised rabbits was found to be less susceptible to be oxidized, having a higher antioxidant capacity than the caged group