Fabio Zicarelli

In vitro fermentation characteristics of diets with different forage/concentrate ratios: comparison of rumen and faecal inocula.

BACKGROUND The aim of this trial was to evaluate the replacement of rumen fluid with faeces as inoculum in studying the in vitro fermentation characteristics of diets for ruminants using the in vitro gas production technique. Six iso-protein diets with different forage/concentrate ratios were incubated with rumen fluid (RI) or faeces (FI) collected from sheep. RESULTS Most of the fermentation parameters were influenced by diet and inoculum (P < 0.01). With both inocula, organic matter degradability (dOM), cumulative gas production (OMCV) and maximum fermentation rate (R(max) ) increased as the amount of concentrate in the diet increased. R(max) was lower with FI vs RI (P < 0.01); dOM was higher with FI vs RI and the diet × inoculum interaction was significant. As expected, with both inocula, R(max) increased as the neutral detergent fibre content of the diet decreased. Significant correlations were obtained using both inocula between OMCV/dOM and gas/volatile fatty acid (VFA), while the correlation VFA/dOM was significant only with FI. The microbial biomass yield calculated by stoichiometric analysis for all diets was higher with FI vs RI. With FI the organic matter used for microbial growth showed an overall decreasing trend as the amount of concentrate in the diet increased. CONCLUSION The results indicate that both faeces and rumen fluid from sheep have the potential to be used as inoculum for the in vitro gas production technique.

Gas production and organic matter degradability of diets for buffaloes

Riassunto Produzione cumulativa di gas e degradabilità della sostanza organica di diete per bufali. Vengono confrontati i risultati di una prova di produzione cumulativa di gas condotta su tre diete per bufale, caratterizzate da diverso valore nutrivo (0,92, 0,84 e 0,77 UFL/kg s.s.), con quelli stimati a partire dai dati ottenuti per i singoli alimenti costituenti le diete stesse. Mentre non sono emerse differenze tra i valori determinati e quelli stimati per quanto riguarda la degradabilità della sostanza organica e la quantità di gas prodotto a 120 h, i valori determinati della produzione potenziale di gas e del tempo al quale viene raggiunta la velocità massima di fermentazione sono risultati rispettivamente maggiore (P<0,05) e minore (P<0,01) rispetto a quelli stimati. A tali differenze, più evidenti per le diete caratterizzate da maggiore densità energetica, hanno sicuramente contribuito gli effetti associativi degli alimenti.

Comparison of buffalo rumen liquor and buffalo faeces as inoculum for the in vitro gas production technique

Riassunto Liquido ruminale e feci quali inoculi per la gas production. È stato valutato l’impiego delle feci, quale inoculo alternativo al liquido ruminale, per la valutazione degli alimenti zootecnici mediante la tecnica in vitro della produzione cumulativa di gas. Allo scopo sono stati incubati per 120 ore tre alimenti (fieno d’avena, farina di mais e soia f.e.) con 2 pool di liquido ruminale e di feci, prelevati al macello da 8 bufali. Tra i 2 inoculi non sono emerse differenze significative relativamente alla degradabilità della sostanza organica e 0alla maggior parte dei parametri fermentativi. Solo la massima velocità di produzione è risultata significativamente più elevata con le feci (P<0,01). Tali risultati sono in contrasto con quelli della letteratura, forse perché la flora microbica ruminale potrebbe aver risentito maggiormente di quella fecale del digiuno precedente la macellazione.

Effect of non-structural carbohydrate dietary content on the productive performance of Sarda primiparous ewes

Abstract In order to enhance our knowledge of milk sheep rationing, 30 Sarda primiparous ewes, for which single birth was diagnosed by ultrasonography prior to lambing, were divided into two homogeneous groups (L-NSC and H-NSC) and fed isoproteic diets containing different amounts of non-structural carbohydrates (NSC, 36 vs 40 % DM). The lambs were weighed both at birth (between February and March 2002) and at sale (about one month later) in order to estimate milk produced by their mothers during the lactation period, by using a specific equation developed on Sarda ewes. Individual milk yield and quality were then monitored monthly until the ewes dried off (July 2002). Our results showed that group H-NSC (which received the diet with the highest NSC content) was associated to the highest milk yield (P<0.01) during the suckling period. In contrast, in the milking period group L-NSC showed significantly higher (P<0.05) mean milk yield (996.2 vs 899.8 g/d) and fat and protein corrected milk yield (979.6 vs 877.7 g/d). Dietary treatments did not significantly affect milk composition. In conclusion, considering the milk production of each group as a function of the lactation month, group H-NSC had its best performance during the first two months of lactation, while group L-NSC was more productive during the remaining months. Also the percentage of protein, fat and casein of the milk during milking showed a similar trend. While the latter parameters were higher in the H-NSC group during the first two months of milking, from the 4th control onward higher levels were observed in the L-NSC group. These results suggest, at least for Sarda primiparous ewes, the adoption of diets with different contents of non-structural carbohydrates according to the productive period (40 %, DM basis, in the first two months of lactation, 36 %, DM basis, in subsequent months).

Starter protein concentration and weaning of buffalo calf

Abstract The authors described the harmonic growth in terms of biological efficiency of growth (BEG), live weight, body weight gain and morphological measuraments of 16 buffalo female calves (age in days: 49.0 ±1.3) divided in two groups of feeding. The T group recieved a concentrate with 28.5 % of crude protein on the dry matter basis, while the C group recieved a concentrate with 21.0 % of crude protein on dry matter basis; moreover the concentrate of the T group presented an high quantity of non proteic nitrogen (NPN) (33% of crude protein). Blood samples for haematological parameters were collected. No differences in terms of growth, BEG, live weight, body weight gain and morphological measuraments were found. Only the nitrogen blood values in the T group resulted significatively higher then C group (8.53 mmol/L vs. 4.66 mmol/L, respectively). This study confirms the importance of protein source for the formulation of the starter concentrate.

Milk protein and cheese yield in buffalo species

Abstract Buffalo milk samples differing significantly for cheese yield values were analysed by 2D electrophoresis in order to outline a protein profile, with specific regards to k-casein fractions. Four buffaloes, two of which showing high cheese yield and two with low cheese yield selected from a group of 135 subjects were chosen for the proteomic analyses. Six main spots in 2D gels were recognized as αs1-, αs2-, β- and k-casein, α-lactoalbumin, β-lactoglobulin. The main visible differences in the 2D gels between buffaloes with high vs. low cheese yield were found in the appearance of the four k-casein spots (spots numbers:20, 19, 16, 18) which differ in the number of phosphorilation and glycosilation. The area and the intensity of the four spots were calculated by using Melanie II (Bio-Rad) software. Samples with high cheese yield showed higher value of the by-products: area x intensity of spot 16, correspondent to k-casein with one phosphorilation site, and lower values of spots 19 and 20, of k-casein with more than one phosphorilation site and glycosilated.

Incidence of pregnancy failures in buffaloes with different rearing system

During a three year trial, 380 corpora lutea were found in lactating buffaloes and the ratios of not pregnant buffaloes/corpora lutea (NP/CL) were analysed by chi-square test between: years (1999 vs. 2000 vs. 2001), days open (<120 days vs. >120 days; DO1 and DO2 groups respectively), January–March vs. April–August calving periods, presence vs. absence of swimming-pool (G1 group vs. G2 group respectively). Data were analysed by chi-square test. NP/CL ratios increased throughout the years (7.53%A vs. 26.32%Bb vs. 41.73%Bc in 1999, 2000 and 2001 respectively) due to a progressive paddock overcrowding and were higher in DO2 groups and during the January-March period. The swimming pool presence was able to reduce significantly the NP/CL incidence (18.01%A vs. 33.14%B in G1 and G2 groups, respectively) with a significant effect only in the April-August period (18.62%A vs. 34.96%B in G1 and G2 respectively). NP/CL ratio, as expression of anomalous oestrous cycle and embryonic mortality, may be proposed as a specific tool for evaluating buffalo welfare.

Effects of space availability on productive and reproductive performances in buffalo cows

Abstract The effects of space availability on productive and reproductive performances have been evaluated in buffalo cows. The trial was carried out on 124 lactating buffaloes (69±84 days in milk) equally divided in two experimental groups (group 1 and group 2) with different space availability (15 vs 20m2/ head). Daily milk production was recorded in each group and a sample of milk was monthly analysed for fat and protein contents. Furthermore, fertility and intercalving and start trial-conception (number of days from the beginning of the trial until conception) intervals were also evaluated. Statistical analysis was performed by ANOVA with repeated measures for productive parameters and by Student’s t Test for intercalving and start trial-conception intervals. Buffaloes in Group 2 showed higher (P<;0.05) milk production in both the initial (74 to 104 days in milk) and final (around 230 days in milk) phases of the lactation curve compared to animals in Group 1. No differences emerged for qualitative characteristics of milk and reproductive parameters. In conclusion the increase of space availability improve animal milk yield in buffalo cows while reproductive performances are not modified.

Relationship among the cheese yield, the characteristics of the curd and those of buffalo milk

Abstract Correlation coefficients were evaluated between the theoretical cheese yield (ThCY), the real yield at 4 (FCY) and 28 h (28CY), the curd dry matter (CDM) and the relationships with the percentage of proteins and milk characteristics. Milk samples were collected every 50 days from 60 buffaloes (326 samples) that were half-sibs (through paternal or maternal lineage ascertained by DNA test), bred in two farms. Positive correlations were found between FCY and 28CY and the enzymatic phase of coagulation and with the milk content in DM, proteins, casein and lipids. Negative correlations were found with lactose and urea milk content. These yields increased when the percentage of DM, proteins and hash of the curd were lower and that of lipids was higher. The 28CY is correlated with ThCY (r = 0.762; P < 0.01) and with the CDM (r = 0.809; P < 0.01). A high 28CY was also characterized by a high 28CY/% proteins ratio and CDM/% proteins ratio. The CDM was higher when the DM of milk and its content in proteins, casein and lipids were higher and when the content in lactose was lower. A correlation (r = 0.501; P < 0.01) was observed between the CDM and the DM percentage of the curd. For the other components the correlations found were the same as for the 28CY. The 28CY/% proteins enhanced at the increasing lipid content of the milk (r = 0.417; P < 0.01) and at decreasing content in urea (r = - 0.317; P < 0.01) and freezing point (r = - 0.123; P < 0.01). The CDM /% proteins was positively influences by fat (r = 0.596; P < 0.01) and lactose (r = - 0.341; P < 0.01). The ThCY/28CY was negatively influenced by “R” and by the pH value and positively correlated with the lipid content of milk.

Relationships between buffalo milk components and curd characteristics

Abstract The aim of this study was to evaluate the coefficients of correlation between curd chemical composition and milk characteristics, theoretical and real cheese yield and ratios between cheese yield and protein percentage. The analysis were performed on 326 milk samples collected from 60 half sib buffaloes, ascertained by DNA test, every 50 days. The percentages of dry matter, proteins and fat of the curd were inversely correlated to the curd firmness (a30), a low enzymatic phase of coagulation and low pH value. Percentage of dry matter in the curd was positively correlated with proteins, casein and fat of the milk and negatively with lactose. Furthermore, dry matter and proteins percentages are also positively correlated with theoretical cheese yield and its ratio with real cheese yield, curd dry matter from 1 litre of milk and the ratio between curd dry matter and protein percentage. Negative correlations were found with real cheese yield at 28 hours (r = - 0.100; P< 0.01) and its ratio with protein percentage. An inverse relationship was highlighted between curd proteins percentage and fat of either milk and curd, while a direct association was present with lactose. A higher protein percentage in the curd was linked to a lower cheese yield and a lower ratio between cheese yield and proteins. Ash of the curd, finally, showed similar association to those described for proteins.