Effect of varying dietary Azolla levels on growth, carcass characteristics, blood biochemical parameters and digestive enzymes of growing Egyptian geese

The present study was performed to determine the influence of dietary levels of Azolla on growth performance, blood parameters and digestive enzymes of growing geese. At 4 weeks old, 120 Egyptian goslings were randomly distributed to 4 groups, 30 to each group. Geese were fed four levels of Azolla (0, 4, 8 and 16%) during the experimental period (4-12 weeks of age). No significant differences were noticed among the experimental groups on growth parameters except body weight gain (BWG) during 4-8 wk of age and feed intake (FI) at 8-12 wk of age. Plasma total protein (TP), globulin, total cholesterol (TC) and low density lipoprotein (LDL) levels were significantly increased by 8% Azolla level. However, urea level was significantly decreased in geese fed on 8% and 16% Azolla levels compared to 4% level and control group. Super oxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), immunoglobulin (IgG), and lysozyme were significantly reduced by all dietary Azolla levels supplementation. Digestive enzymes were statistically affected by Azolla levels. It can be concluded that use of Azolla in Egyptian geese diets at 8 and 16% achieved positive effects on growth performance and most of blood biochemical parameters during the fattening period.

Effect of dietary calcium and phosphorus levels on growth, carcass characteristics and liver and kidney functions of growing Egyptian geese

The present study investigated the effect of different dietary levels of calcium (Ca) and non-phytate phosphorus (P) on the growth performance, carcass characteristics, and blood components of growing geese. A total of 120, 4-wk-old Egyptian goslings with similar body weights were randomly distributed to four groups in a 2 × 2 factorial arrangement, which included 2 levels of Ca (0.85% and 0.70%) and 2 levels of non-phytate P (0.45% and 0.35%). Each group was subdivided into 6 replicates of five birds. The experiment lasted 8 wk, from 4 to 12 wk of age. Results show that dietary Ca level had no significant effect on any of the studied growth performance traits over the full experimental period. Dietary P level also had no significant impact on these traits, with the exception of daily body weight gain and feed conversion ratio at 8 to 12 wk of age; these improved significantly with the low P diet. Geese received a diet containing 0.70% Ca + 0.45% P had the lowest body weight values at 12 wk of age and the lowest daily body weight gain, and feed intake at 8 to 12 weeks of age. While, the lowest value of feed conversion ratio was recorded in geese fed low level of Ca with low level of P (0.70% Ca + 0.35% P). There were no significant effects of the different dietary levels of Ca, P, or their interaction on all studied carcass parameters. Low dietary Ca level significantly increased the plasma levels of total protein, albumin, alanine transaminase (ALT), aspartate transaminase (AST), and creatinine and significantly decreased the plasma levels of Ca and P. Different dietary P levels had no significant effect on plasma levels of albumin, AST, ALT, ALP, and urea, whereas the 0.35% P-based diet significantly decreased the plasma contents of total protein, creatinine, Ca, and P. Plasma levels of albumin, creatinine, urea, Ca, and P were not affected by an interaction between Ca and P. Diets containing 0.70% Ca and 0.45% P lead to the highest plasma values for total protein, ALT, AST, and ALP compared with the other dietary Ca and P combinations. In conclusion, dietary Ca and P levels can be simultaneously reduced without negative impacts on growth performance, carcass characteristics, or blood biochemical components. We advise to avoid increasing the dietary Ca: P ratio, as it leads to negative effects on growth performance and blood biochemistry in growing geese. So, the findings of the current study recommended the low levels of Ca (0.70%) and non-phytate P (0.35%) for the performance of Egyptian geese during the fattening period.

The intestinal microbial composition in Greylag geese differs with steatosis induction mode: spontaneous or induced by overfeeding

Background

Relationships between microbial composition and steatosis are being extensively studied in mammals, and causal relations have been evidenced. In migratory birds the liver can transiently store lipids during pre-migratory and migratory phases, but little is known about the implications of the digestive microbiota in those mechanisms. The Landaise greylag goose (Anser anser) is a good model to study steatosis in migratory birds as it is domesticated, but is still, from a genetic point of view, close to its wild migratory ancestor. It also has a great ingestion capacity and a good predisposition for hepatic steatosis, whether spontaneous or induced by conventional overfeeding. The conventional (overfeeding) and alternative (spontaneous steatosis induction) systems differ considerably in duration and feed intake level and previous studies have shown that aptitudes to spontaneous steatosis are very variable. The present study thus aimed to address two issues: (i) evaluate whether microbial composition differs with steatosis-inducing mode; (ii) elucidate whether a digestive microbial signature could be associated with variable aptitudes to spontaneous liver steatosis.

Results

Performances, biochemical composition of the livers and microbiota differed considerably in response to steatosis stimulation. We namely identified the genus Romboutsia to be overrepresented in birds developing a spontaneous steatosis in comparison to those submitted to conventional overfeeding while the genera Ralstonia, Variovorax and Sphingomonas were underrepresented only in birds that did not develop a spontaneous steatosis compared to conventionally overfed ones, birds developing a spontaneous steatosis having intermediate values. Secondly, no overall differences in microbial composition were evidenced in association with variable aptitudes to spontaneous steatosis, although one OTU, belonging to the Lactobacillus genus, was overrepresented in birds having developed a spontaneous steatosis compared to those that had not.

Conclusions

Our study is the first to evaluate the intestinal microbial composition in association with steatosis, whether spontaneous or induced by overfeeding, in geese. Steatosis induction modes were associated with distinct digestive microbial compositions. However, unlike what can be observed in mammals, no clear microbial signature associated with spontaneous steatosis level was identified.

Consequences of varying dietary crude protein and metabolizable energy levels on growth performance, carcass characteristics and biochemical parameters of growing geese

This research aimed to investigate the effect of varying dietary crude protein (CP) and metabolizable energy (ME) quantity on growth, carcass characteristics, biochemical blood parameters and molecular aspects of growing geese. Overall, a total of 180 Egyptian goslings were used in a 2 × 3 factorial design. Two levels of CP (18% and 16%) and three levels of ME (3000, 2900 and 2800 kcal/kg diet) were employed. Growth traits showed no significant differences as a result of different CP or ME levels. Birds fed the higher CP level consumed more feed than the lower. Carcass, dressing, heart, spleen, abdominal fat and thigh percentages within the group fed 18% CP were higher than the other group. Compared with the other ME-based diet, geese fed a low-ME based diet had the highest heart percentage. Feeding growing geese on a 2900 Kcal/kg ME-based diet increased the serum content of total protein and globulin. Geese fed the high-ME diet showed the highest levels of ALP and C4 as compared with other ME levels. Regarding Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), different protein and energy levels did not affect the molecular weight of blood proteins of Egyptian geese during the growing phase. It could be concluded the levels of 16% CP and 2800 kcal/kg ME are enough to maintain the growth performance and the other physiological indices as well as molecular aspects.

Comparison of the composition and sensory characteristics of goose fatty liver obtained by overfeeding and spontaneous fattening1

Spontaneous liver steatosis can be experimentally induced in domestic Greylag geese by combining a short photoperiod with a sequence of feed restriction followed by ad libitum corn feeding. This could offer an alternative to the conventional "foie gras" production system based on overfeeding. The present work aimed at comparing the compositional characteristics, sensory profile, and acceptability by a consumer panel of fatty livers obtained by overfeeding and spontaneous fattening. In all, 210 male geese were used: 125 geese were raised over a 31-wk period to produce fatty liver without overfeeding ("alternative livers") and 85 were raised using conventional methods with overfeeding ("conventional livers"). Mean liver weight was over 1 kg (1,102 g) in the conventional group and 445 g in the alternative group. The characteristics of the livers were studied in 2 subpopulations: 44 conventional livers representative of the experimental population (mean liver weight 1,064 g) and 42 alternative livers weighing more than 400 g (mean 702 g). Compared with the alternative livers, livers from the conventional group showed significantly (P < 0.05) higher dry matter and lipid contents, lighter color (L*), and lower yellowness (b*). The neutral lipids of alternative livers contained significantly less triglycerides and free fatty acids and significantly more cholesterol and cholesterol esters than those from conventional livers. Detailed analysis of the fatty acid composition of triglycerides showed that the proportion of mono- and polyunsaturated fatty acids was significantly higher in the alternative livers. However, covariance analysis suggested that these differences in lipid composition were mainly due to differences in lipid content between both types of livers. The evaluation of cooked livers by a trained expert panel revealed significant differences in the sensory profile between the conventional and alternative livers. The acceptability by a consumer panel was significantly lower in alternative compared to conventional livers. This difference was not related to weight and/or lipid content since livers of similar weight range (800 to 1,000 g) were compared and showed clear-cut differences for hedonic scores.

Evolution of intestinal microbiota and body compartments during spontaneous hyperphagia in the Greylag goose

The aim of this work was to study the effects of spontaneous hyperphagia on the evolution of intestinal microbiota and body compartments in old goose. From October 25th to November 26th, 5-yr-old breeding Greylag Landaise geese (106 males and 106 females) were fed with grass during 1 mo (G period). From November 26th (0 d) the birds had ad libitum access to pellets (AMEn: 10.5 MJ/kg, CP: 18.9 g/kg; spontaneous fattening (SF) period). Some birds were killed at -31 d (n = 24; 50/50 sex ratio), 0 d (n = 48), 14 (n = 46), 22 d (n = 46), and 70 d (n = 48) after the start of G period to measure body traits. For microbial analysis, 10 of the samples per sex at 0 d, 14 d, and 70 d were selected to be representative of body traits. Between 0 and 22 d, liver weight increased from 98 g to 194 g in males and from 89 g to 199 g in females (P < 0.001). Liver weight decreased between 22 and 70 d from 194 to 174 g in males and from 199 to 163 g in females (P < 0.001). Irrespective of the diet (G or SF period) and the sex of the bird, the two major phyla were Proteobacteria (49%) and Firmicutes (48%). Bacteroidetes represented around 3.0% of the sequences. At order level, Firmicutes were dominated by Clostridiales (33% of total sequences) and Lactobacillales (13% of total sequences) and Proteobacteria were dominated by Campylobacteriales (34% of total sequences). Finally, Bacteroidetes were dominated by Bacteroidales. SF and sex did not change the microbial diversity but sparse partial least squares discriminant analysis allowed us to highlight discriminant operational taxonomic unit between experimental groups. In conclusion, our result showed that changes in the body compartments of old geese during spontaneous hyperphagia depend on the sex of the birds, but not so much in gut microbial composition. Further investigations are necessary to understand the functional microbiota and highlight the role of gut microbiota in hepatic steatosis induced with hyperphagia in geese.