The purpose of this paper was to evaluate the effects of saponin-based additive: during mid- lactation and peri-parturient period. Two experiments were carried out with 31 dairy Saanen and Alpine goats which were assigned to a control group (C group) or a group treated with saponin (S group). Experiment 1 consisted of 20 dairy goats (C group, n=10; S group, n=10) in lactation and experiment 2 had an overall number of 24 pregnant goats, including 13 goats from experience 1, around parturition (C group, n=12; S group, n=12). S group received the saponin additive powder blended with the total mixed ration at a dose of 25g/animal per day, whereas the C group was only given the standard diet. After one week of adaptation, the daily administration of saponin additive was conducted during four consecutive weeks followed by one or two weeks of wash-out. Blood and rumen fluid samples were taken weekly from both groups to perform a metabolic screening. The plasma samples were analyzed for: glucose, non-esterified fatty acids (NEFA), ?-hydroxybutyric acid (?HB), total cholesterol (TC), high-density lipoprotein (HDL), total bilirubin (TB), total proteins (TP), albumin, haptoglobin (Hp), urea, aspartate-aminotransferase (AST), gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), total calcium (Ca), magnesium (Mg3+), phosphorus (PO43-). Rumen sample analyses involved pH and ammonia nitrogen (NH3) determinations, concentration of volatile fatty acids (VFA) and total protozoa counts. Feed samples, milk yield (MY) and body weight (BW) were measured on a weekly basis. Throughout both experimental periods, all the goats were clinically healthy. Statistical analyses were performed using the linear mixed model procedure of SAS. The results of the first experiment with lactating goats showed no saponin effect among the zootechnical measures, plasma biochemical metabolites (glucose, NEFA, ?HB and urea) and ruminal fermentation parameters (p>0.05). However, there was a tendency for the acetate to propionate ratio (S < C, p=0.0570). The results showed an important time effect on BW, MY, glucose, NEFA and all ruminal fermentation parameters (p<0.05), with the exception of caproic acid (p>0.05). This time effect, which is mainly associated with the last week of the experiment, could be due to a high temperature during this week. In the second experiment there was an absence of saponin effect on almost all blood metabolites (p>0.05), except for plasma urea (S > C, p=0.0544). Concerning ruminal fermentation parameters, only total protozoa showed a tendency (S > C, p=0.096). A time effect was observed for most of zootechnical, plasmatic and ruminal variables around parturition because of the physiological imbalances during this transition period (p<0.05), with the exception of GGT, Mg3+ and total protozoa count (p>0.05). Hence, it was concluded that the daily administration of saponin additive during four consecutive weeks in mid-lactation and peri-partum in Saanen and Alpine dairy goats had not influenced plasma metabolites and ruminal fermentation parameters; neither did it influence the zootechnical animal performance. The observed tendencies for a saponin effect in relation to blood urea, total protozoa count and acetate/propionate ratio were relevant in this current research. The potential of saponin additive to improve efficiency of ruminal fermentation through increased microbial protein synthesis could be dependent on the dose, the period of administration and the type of basal diet feed.
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