Paolo Bani

Experimental acute rumen acidosis in sheep: Consequences on clinical, rumen, and gastrointestinal permeability conditions and blood chemistry

Acute acidosis was induced in sheep, and gastrointestinal permeability was assessed by using lactulose as a permeability marker. Metabolism was evaluated by monitoring blood metabolites. Four rams (72.5 ± 4.6 kg BW) were used in a 2 × 2 changeover design experiment. The experimental period lasted 96 h from -24 to 72 h. After 24 h of fasting (from -24 to 0 h) for both controls and acidosis-induced rams (ACID), 0.5 kg of wheat flour was orally dosed at 0 and 12 h of the experimental period to ACID, while the basal diet (grass hay, ad libitum) was restored to control. At 24 h, a lactulose solution (30 g of lactulose in 200 mL of water) was orally administered. Blood samples were collected at -24, 0, 24, 48, and 72 h of the experimental periods for the analysis of metabolic profiles and during the 10 h after lactulose dosage to monitor lactulose changes in blood. In addition, rumen and fecal samples were collected at 24 h of the experimental period. The acidotic challenge markedly reduced (P < 0.01) rumen pH and VFA but increased rumen d- and l-lactic acid (P < 0.01). Concurrently, a decrease of fecal pH and VFA occurred in ACID (P < 0.01), together with an abrupt increase (P < 0.01) of lactate and fecal alkaline phosphatase. Blood lactulose was significantly increased in ACID peaking 2 h after lactulose dosage. Blood glucose, β-hydroxybutyrate, Ca, K, Mg, and alkaline phosphatase showed a significant reduction (P < 0.05) at 24 h, whereas urea and NEFA declined (P < 0.05) from 48 to 72 h. A strong inflammatory acute phase response with oxidative stress in ACID group was observed from 24 to 72 h; higher values of haptoglobin (P < 0.01) were measured from 24 to 72 h and of ceruloplasmin from 48 (P < 0.05) to 72 h (P < 0.01). Among the negative acute phase reactants, plasma albumin, cholesterol, paraoxonase, and Zn concentration also decreased (P < 0.05) in ACID at different time points between 24 and 72 h after acidotic challenge start. A rise (P < 0.05) of reactive oxygen metabolites and a drop of vitamin E (P < 0.01) between 24 and 72 h were indicative of oxidative stress in ACID. The perturbation of these blood metabolites suggests that acute acidosis was effectively induced by our model. The increase of lactulose in blood in ACID indicates that gastrointestinal permeability for the marker increased and the large increment after 2 h from dosage suggests that most of the passage occurred through the rumen or abomasal walls.

Selection for milk coagulation properties predicted by Fourier transform infrared spectroscopy in the Italian Holstein-Friesian breed

Milk coagulation is based on a series of physicochemical changes at the casein micelle level, resulting in formation of a gel. Milk coagulation properties (MCP) are relevant for cheese quality and yield, important factors for the dairy industry. They are also evaluated in herd bulk milk to reward or penalize producers of Protected Designation of Origin cheeses. The economic importance of improving MCP justifies the need to account for this trait in the selection process. A pilot study was carried out to determine the feasibility of including MCP in the selection schemes of the Italian Holstein. The MCP were predicted in 1,055 individual milk samples collected in 16 herds (66 ± 24 cows per herd) located in Brescia province (northeastern Italy) by means of Fourier transform infrared (FTIR) spectroscopy. The coefficient of determination of prediction models indicated moderate predictions for milk rennet coagulation time (RCT=0.65) and curd firmness (a₃₀=0.68), and poor predictions for curd-firming time (k₂₀=0.49), whereas the range error ratio (8.9, 6.9, and 9.5 for RCT, k₂₀, and a₃₀, respectively) indicated good practical utility of the predictive models for all parameters. Milk proteins were genotyped and casein haplotypes (αS₁-, β-, αS₂-, and κ-casein) were reconstructed. Data from 51 half-sib families (19.9 ± 16.4 daughters per sire) were analyzed by an animal model to estimate (1) the genetic parameters of predicted RCT, k₂₀, and a₃₀; (2) the breeding values for these predicted clotting variables; and (3) the effect of milk protein genotypes and casein haplotypes on predicted MCP (pMCP). This is the first study to estimate both genetic parameters and breeding values of pMCP, together with the effects of milk protein genotypes and casein haplotypes, that also considered k₂₀, probably the most important parameter for the dairy industry (because it indicates the time for the beginning of curd-cutting). Heritability of predicted RCT (0.26) and k₂₀ (0.31) were close to the average heritability described in literature, whereas the heritability of a₃₀ was higher (0.52 vs. 0.27). The effects of milk proteins were statistically significant and similar to those obtained on measured MCP. In particular, haplotypes including uncommon variants showed positive (B-I-A-B) or negative (B-A(1)-A-E) effects. Based on these findings, FTIR spectroscopy-pMCP is proposed as a potential selection criterion for the Italian Holstein.

In Vitro Rumen Fermentation Characteristics of Some Naturally Occurring and Synthetic Sugars

Soluble sugars are thought to play an important role in the fermentation processes of the rumen but their actual fermentation rate has not been fully assessed. Some sugars are also used as markers to assess gut permeability in monogastrics but their use in ruminants can be compromised by the hydrolytic activity of rumen microflora. This study aimed to evaluate the fermentability of some naturally occurring and synthetic soluble sugars. The synthetic soluble sugars were included to verify their possible use as markers for studies of gut permeability in ruminants. In vitro gas and volatile fatty acid (VFA) production from glucose, fructose, xylose, galactose, sucrose, lactose, arabinose mannitol, lactulose and sucralose were measured in a 24 h-incubation trial using ruminal fluid from heifers adapted or not-adapted to additional sugars in the diet, and with caecal content as inocula. Gas production from the same sugars was further evaluated in a 72 h-incubation trial with not-adapted rumen fluid only. Gas and VFA production were not affected by feeding additional sugars, but significant effects of inocula (ruminal vs caecal), sugars and their interaction were observed. Caecal inoculum produced less gas but higher VFA than ruminal inocula. Fructose and glucose had the highest rates of gas production (10.57% h–1 and 10.42% h–1, respectively), and lactulose and mannitol the lowest (3.47% h–1 and 4.63% h–1, respectively) when fermented with ruminal fluid. Sucralose seemed to have a negative effect on microbial fermentations. Our results indicate that lactulose and mannitol might largely escape rumen fermentation, suggesting their possible use as markers to test gut permeability also in ruminants. This needs to be verified in vivo.

Assessment of gastrointestinal permeability by lactulose test in sheep after repeated indomethacin treatment.

The aim of the study was to assess the small intestine permeability by using lactulose as a sugar probe and blood metabolites in sheep after a challenge with repeated indomethacin injections. According to a changeover design, 7 adult sheep (4 males and 3 females) were subjected to 4 intramuscular injections (every 12 h) of saline [control (CRT); 7 animals] or indomethacin (INDO; 7 animals). Two hours after the last injection, 30 g of lactulose were administered orally to both CTR and INDO. Blood samples were collected daily for the analysis of the metabolic profile and 5 samples were collected at 2-h intervals following lactulose ingestion to monitor changes in blood levels of lactulose as an index of intestinal permeability. The INDO challenge induced clinical symptoms such as lack of appetite, dullness, weakness, depression, and diarrhea with traces of blood in the feces. In INDO group, haptoglobin and ceruloplasmin increased (P < 0.01) after INDO challenge whereas a decrease (P < 0.05) of negative acute phase reactants (e.g., cholesterol, albumin, and paraoxonase) was observed. Reactive oxygen metabolites increased (P < 0.01) from 60 to 204 h after the INDO challenge start, with a decrease of vitamin E concentration from 12 (P < 0.01) to 132 h (P < 0.05). Blood lactulose concentrations were increased (P < 0.05) in INDO animals and the highest mean values (17.67 µg/mL in INDO vs. 0.17 µg/mL in CRT; P < 0.01) were observed 6 h after oral dosage of lactulose. These changes indicate that the INDO challenge led to severe inflammatory responses with oxidative stress by enhancing small intestinal permeability in sheep that allowed lactulose to enter in blood. The results of this experiment demonstrate that lactulose can be used as a probe to assess gastrointestinal permeability in adult ruminants to test the consequences of stressing conditions on animal welfare. For this purpose, the most suitable time for blood sampling is between 2 and 8 h after the oral dosage of lactulose.

Improving the prediction ability of FT-MIR spectroscopy to assess titratable acidity in cow's milk.

This study investigated the potential application of Fourier transform mid-infrared spectroscopy (FT-MIR) for the determination of titratable acidity (TA) in cows milk. The prediction model was developed on 201 samples collected from cows in early and late lactation, and was successively used to predict TA on samples collected from cows in early lactation and in samples with high somatic cell count. The root mean square error of cross-validation of the model by using external validation dataset was 0.09 °Soxhlet-Henkel/50 mL. Applying the model on milk samples from cows in early lactation or with high somatic cell count, the root mean square error of prediction was 0.163 °Soxhlet-Henkel/50 mL, with a RER and RPD of 23.9 and 5.1, respectively. Our results seem to indicate that FT-MIR can be used in individual milk samples to accurately predict TA, and has the potential to be adopted to measure routinely the TA of milk.

Variations of some blood parameters in rabbit reared under different environmental conditions

Riassunto Variazioni di alcuni parametri ematici in conigli allevati in differenti condizioni ambientali. Presso un allevamento commerciale di conigli, una medesima prova di allevamento è stata condotta, dallo svezzamento a fine ingrasso, in condizioni di clima fresco e caldo, controllando accrescimenti, consumi alimentari, caratteristiche del contenuto ciecale e profilo metabolico. Lo stress da caldo ha indotto variazioni nei parametri ematici solo in parte correlabili al riscontrato calo di ingestione. Le più consistenti relazioni tra caratteristiche del contenuto ciecale e variazioni metaboliche in condizioni di stress termico indicano una maggiore criticità delle caratteristiche delle diete in tali situazioni.

Can a single rumen sample really diagnose SARA in commercial farms

The accuracy of diagnosis of subacute rumen acidosis (SARA) with a single measurement of the ruminal pH remains contradictory. To clarify this aspect, a large assessment of rumen, faecal and blood parameters was performed in several herds characterised by diets rich in non-structural carbohydrates. Rumen fluid was collected by rumenocentesis 6 h after feeding from 114 dairy cows (half 30–90 and half 150–250 days in milk) from 10 herds. In the same day, blood and faecal samples were collected and milk yield was recorded. The herds were ex-post classified as healthy (CTR n = 6) or as at risk for SARA (n = 4), based on ruminal pH. SARA versus CTR herds had lower rumen pH (5.67 vs 5.97 P < 0.01) and higher concentration of VFA, with lower acetate (P < 0.01) and higher propionate and valerate (P < 0.05) proportions. Moreover, the faecal DM was lower (P < 0.05), whereas the milk yield was higher with a lower concentration of fat (P < 0.05). At blood level, no significant differences were observed between the groups on positive acute-phase proteins, whereas SARA herds showed higher concentrations of paraoxonase and Ca and lower of cholesterol, total proteins, nitrates, Na and Zn (P < 0.01). Therefore, SARA herds did not show any evident symptom of ruminal disorder or systemic inflammation. On the contrary, these herds had a higher milk yield and a better inflammometabolic profile. These data confirm the difficulties to diagnose the SARA by a single measurement of ruminal pH in commercial herds and suggest the need of more specific indices to identify herds at risk.

Metabolic and biochemical changes in plasma of the periparturient rabbit does with different litter size

The aim of this study was to investigate the metabolic and biochemical changes in plasma that occur in the reproductive rabbit doe close to the parturition, as well as if the number of offspring affects the metabolism and the health status of the doe. At -3, 4 and 12 days from parturition (-D3, D4, and D12, respectively) nine rabbit does at their third parity from a commercial hybrid line (HYPLUS PS 19) selected for high prolificacy were weighted and blood was collected for a wide inflammometabolic profile. According to the number of offspring the does were retrospectively divided in two groups: high litter size group (HI; n=5) and low litter size group (LO; n=4). BW was higher (P<0.01) at -D3 and had the lowest values at D4. At D12, the BW was lower (P<0.05) in LO compared with HI. Several metabolites significantly changed from dry to lactation period. Glucose and cholesterol had the lowest levels at -D3; non-esterified fatty acid (NEFA) and aspartate aminotransferase had the highest values before parturition (P<0.05); creatinine and β-hydroxybutyrate (BHBA) were higher at -D3 with respect to D4 (P<0.05). The lowest value of paraoxonase was observed in does at -D3 (P<0.05), whereas at this time ceruloplasmin and total bilirubin had the highest concentration (P<0.05). The differences for blood profile parameters between does grouped according to litter size were mainly evident before parturition (-D3). In particular, BHBA, NEFA and total bilirubin had higher concentrations (P<0.05) in HI v. LO group, whereas albumin and PON were lower in HI group (P<0.01). After parturition there were no significant differences for the metabolic parameters between the two groups. The results show that for reproductive rabbit doe the last days of gestation are very stressful from a metabolic and inflammatory point of view. The genetic selection of does for higher litter size has increased their ability to mobilize body reserves in order to guarantee the nutrients to a high number of kits. This exposes them to a more severe metabolic and inflammatory challenge during the transition period. Consequently, feeding and managerial strategies for high prolificacy periparturient rabbit does should be revised.

Effects of hybrid and maturity stage on in vitro rumen digestibility of immature corn grain

This study aimed to evaluate the influences of hybrids (HYB) and maturity stage (SAMP) on in vitro rumen digestibility of immature corn grain. Four HYB (Gigantic, Y43, Klips and 9575) from the FAO group 700 were grown under identical agronomic conditions. First sampling (T1) was done after 95 days from seedling and then 4, 8, 13, 18 and 27 days later (T2 to T6). In vitro starch digestibility (STD_7h) and gas production (72 h) were measured. Whole plant and grain dry matter (WP_DM and GR_DM, respectively) and zein content were significantly affected (P<0.01) by HYB and SAMP. Starch content was significantly affected by HYB, SAMP and their interaction. It increased from T1 to T4 (from 67.47 to 72.82% of GR_DM) and then tended to plateau. Concurrently, STD_7h significantly decreased with advancing SAMP and was also affected by HYB. With advancing maturity, total volatile fatty acids (VFA) significantly decreased, with an increase of acetate and a decrease of propionate molar proportion (P<0.01). Gas production rate (GP_c) was significantly affected by HYB, SAMP and HYB×SAMP. Whole plant grain DM correlated (P<0.01) positively with grain starch content (r=0.60 and 0.64) but negatively with STD_7h (r=-0.39 and r=-0.63) and VFA concentration (r=-0.59 and -0.75). Zein percentage in crude protein negatively affected (P<0.01) total DM (r=-0.65,), STD_7h (r=-0.73) and GP_c (r=-0.68). Results suggest that genotypes and maturity stages influence DM and rumen starch digestibility of immature corn grain and in this respect zein can play a significant role.

Genetic and environmental influences on in vitro digestibility of alfalfa

Abstract To study the relationships between in vitro NDF or true dry matter digestibility (NDFD and IVTDMD) and forage fibre content, 95 alfalfa samples from 5 cultivars grown in 3 different locations and from different cuts were analysed for fibre fractions and evaluated for NDFD and IVTDMD. NDFD was mainly influenced by order of cut and age of the fields. The multifoliate cultivar controlled did not appear to differ for fibre composition and NDFD from the other ones. Fibre fractions contents explained a large part of the difference in NDFD and IVTDMD, and no significant differences in this relationships appeared for first-cut vs. aftermath forage. The best predictive equation of NDFD from fibre factions was: NDFD = 73.61 -0.62 * NDF (% DM) – 56.33 * ADL/NDF (R2=0.39). Variations in fibre content and quality do not completely explain differences in NDFD suggesting the interference of other factors that are worth to be better studied.