Use of weaning concentrate in the feeding suckling kids: effects on meat quality

The effect of a feeding supplementation with starter concentrate on “Capretto” meat production and its qualitative characteristics was investigated. The results showed that the effect of concentrate supplementation did not influence the slaughter weight, slaughter and dissection data, tissue composition and meat chemical composition of the pelvic limb. No differences were found for rheological characteristics of LD meat, except cohesiveness values, which were higher in the concentrate group kids

Sequence Analysis, Kinetic Constants, and Anion Inhibition Profile of the Nacrein-Like Protein (CgiNAP2X1) from the Pacific Oyster Magallana gigas (Ex-Crassostrea gigas)

The carbonic anhydrase (CA, EC 4.2.1.1) superfamily of metalloenzymes catalyzes the hydration of carbon dioxide to bicarbonate and protons. The catalytically active form of these enzymes incorporates a metal hydroxide derivative, the formation of which is the rate-determining step of catalytic reaction, being affected by the transfer of a proton from a metal-coordinated water molecule to the environment. Here, we report the cloning, expression, and purification of a particular CA, i.e., nacrein-like protein encoded in the genome of the Pacific oyster Magallana gigas (previously known as Crassostrea gigas). Furthermore, the amino acid sequence, kinetic constants, and anion inhibition profile of the recombinant enzyme were investigated for the first time. The new protein, CgiNAP2X1, is highly effective as catalyst for the CO₂ hydration reaction, based on the measured kinetic parameters, i.e., kcat = 1.0 × 10⁶ s(-1) and kcat/KM = 1.2 × 10⁸ M(-1)·s(-1). CgiNAP2X1 has a putative signal peptide, which probably allows an extracellular localization of the protein. The inhibition data demonstrated that the best anion inhibitors of CgiNAP2X1 were diethyldithiocarbamate, sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid, which showed a micromolar affinity for this enzyme, with KIs in the range of 76-87 μM. These studies may add new information on the physiological role of the molluskan CAs in the biocalcification processes

Cloning, expression and purification of the α-carbonic anhydrase from the mantle of the Mediterranean mussel, Mytilus galloprovincialis

We cloned, expressed, purified, and determined the kinetic constants of the recombinant α-carbonic anhydrase (rec-MgaCA) identified in the mantle tissue of the bivalve Mediterranean mussel, Mytilus galloprovincialis. In metazoans, the α-CA family is largely represented and plays a pivotal role in the deposition of calcium carbonate biominerals. Our results demonstrated that rec-MgaCA was a monomer with an apparent molecular weight of about 32 kDa. Moreover, the determined kinetic parameters for the CO2 hydration reaction were kcat =  4.2 × 105 s−1 and kcat/Km of 3.5 × 107 M−1 ×s−1. Curiously, the rec-MgaCA showed a very similar kinetic and acetazolamide inhibition features when compared to those of the native enzyme (MgaCA), which has a molecular weight of 50 kDa. Analysing the SDS-PAGE, the protonography, and the kinetic analysis performed on the native and recombinant enzyme, we hypothesised that probably the native MgaCA is a multidomain protein with a single CA domain at the N-terminus of the protein. This hypothesis is corroborated by the existence in mollusks of multidomain proteins with a hydratase activity. Among these proteins, nacrein is an example of α-CA multidomain proteins characterised by a single CA domain at the N-terminus part of the entire protein

A Morphological and Ultrastructural Study of the Anterior Digestive Tract of Adult Nile Tilapia Oreochromis niloticus

Among the most-used fish species in aquaculture is the Nile tilapia, due to its rapid growth rate and its adaptation to a wide range of farming conditions. A careful description of the morphology of the digestive tract, particularly the esophagus and stomach, allows a better understanding of the relationship between structure and function. Combining scanning and light microscopy we highlighted the presence of five different zones in the stomach (1: esophagus-gastric lumen passage; 2: descending glandular portion; 3: fundic portion; 4: ascending glandular portion; 5: gastric-pyloric transition portion). Histochemical investigation showed a secretion of carboxylates mucopolysaccharides along the esophagus and sulphated complex carbohydrates in the stomach. These results suggest that mucins play a protective role of the epithelial lining, which is essential for a correct digestive process. Finally, the characterization of the main cellular structures may be inspiring for more advanced studies aiming to decipher the role of specific molecules, such as neuropeptides, involved in the physiological digestive process

Valutazione dell'attitudine alla caseificazione del latte nel bovino Podolico

L’indagine è stata condotta su 40 bovine podoliche controllate per l’intera lattazione negli anni 1991 e 1992. Per ogni controllo, alla mungitura della mattina e a quella della sera, è stata rilevata la quantità di latte prodotto ed è stato prelevato un campione individuale per la determinazione: (a) della composizione chimica (sostanza secca, residuo secco magro, percentuale di grasso, di proteine e di lattosio), (b) del pH e (c) del profilo lattodinamometrico, attraverso il quale sono state calcolate: (i) la durata della fase enzimatica T; (ii) la velocità di coagulazione K; (iii) la consistenza del coagulo a un tempo definito dall’inizio della coagulazione a. I risultati dell’analisi della covarianza hanno evidenziato che: (a) la distanza dal parto influenza significativamente il valore di tutte le caratteristiche lattodinamometriche considerate; in particolare, all’aumentare dei giorni di lattazione, il latte presenta una più lunga durata della fase enzimatica, una coagulazione più lenta e una minore consistenza del coagulo; (b) la percentuale di grasso e quella di proteine comportano variazioni nella consistenza del coagulo: a una maggiore percentuale di queste due componenti corrispondono, rispettivamente, un minor valore di a20 e un maggior valore di a10; (c) all’aumentare della percentuale di lattosio corrisponde una diminuzione della velocità di coagulazione e della consistenza del coagulo; (d) com’era logico attendersi, l’aumento del pH tende a prolungare la durata della fase enzimatica e a rallentare la velocità di coagulazione, specialmente nella fase iniziale; (e) nelle lattazioni svolte nel 1992, rispetto a quelle del 1991, si osserva, mediamente, un miglioramento della coagulabilità del latte (minore durata della fase enzimatica, più elevata velocità di coagulazione e maggiore consistenza del coagulo; (f) fra gli ordini di parto considerati (1., 2., 3. e 4. e oltre) non si rilevano differenze, tranne che per consistenza finale del coagulo (a30), la quale risulta più elevata nelle bovine di 1. e 2. Parto rispetto a quelle di parto successivo; (g) il turno di mungitura influenza significativamente l’attitudine alla caseificazione del latte, nel senso che il latte munto la sera, rispetto a quello della mungitura della mattina, è caratterizzato da una minore durata della fase enzimatica, da una più elevata velocità di coagulazione e da una maggiore consistenza del coagulo