Institut für Nutztierwissenschaften

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The active core microbiota of two high-yielding laying hen breeds fed with different levels of calcium and phosphorus
(2022) Roth, Christoph; Sims, Tanja; Rodehutscord, Markus; Seifert, Jana; Camarinha-Silva, Amélia
The nutrient availability and supplementation of dietary phosphorus (P) and calcium (Ca) in avian feed, especially in laying hens, plays a vital role in phytase degradation and mineral utilization during the laying phase. The required concentration of P and Ca peaks during the laying phase, and the direct interaction between Ca and P concentration shrinks the availability of both supplements in the feed. Our goal was to characterize the active microbiota of the entire gastrointestinal tract (GIT) (crop, gizzard, duodenum, ileum, caeca), including digesta- and mucosa-associated communities of two contrasting high-yielding breeds of laying hens (Lohmann Brown Classic, LB; Lohmann LSL-Classic, LSL) under different P and Ca supplementation levels. Statistical significances were observed for breed, GIT section, Ca, and the interaction of GIT section x breed, P x Ca, Ca x breed and P x Ca x breed (p < 0.05). A core microbiota of five species was detected in more than 97% of all samples. They were represented by an uncl. Lactobacillus (average relative abundance (av. abu.) 12.1%), Lactobacillus helveticus (av. abu. 10.8%), Megamonas funiformis (av. abu. 6.8%), Ligilactobacillus salivarius (av. abu. 4.5%), and an uncl. Fusicatenibacter (av. abu. 1.1%). Our findings indicated that Ca and P supplementation levels 20% below the recommendation have a minor effect on the microbiota compared to the strong impact of the bird’s genetic background. Moreover, a core active microbiota across the GIT of two high-yielding laying hen breeds was revealed for the first time.
Ceramide metabolism associated with chronic dietary nutrient surplus and diminished insulin sensitivity in the liver, muscle, and adipose tissue of cattle
(2022) Kenéz, Ákos; Bäßler, Sonja Christiane; Jorge-Smeding, Ezequiel; Huber, Korinna
High dietary energy and protein supply is common practice in livestock nutrition, aiming to maximize growth and production performance. However, a chronic nutritional surplus induces obesity, promotes insulin insensitivity, and triggers low-grade inflammation. Thirty Holstein bulls were randomly assigned to two groups, low energy and protein (LEP), and high energy and protein (HEP) intake, provided from the 13th to the 20th month of life. Body weight, carcass composition, laminitis score, and circulating insulin and glucose concentrations were assessed. The expression and extent of phosphorylation of insulin signaling proteins were measured in the liver, muscle, and adipose tissue. The sphingolipid metabolome was quantified by a targeted liquid chromatography-mass spectrometry based metabolomics approach. The HEP bulls were obese, had hyperinsulinemia with euglycemia, and expressed clinical signs of chronic laminitis. In the liver, protein kinase B (PKB) phosphorylation was decreased and this was associated with a higher tissue concentration of ceramide 16:0, a sphingolipid that diminishes insulin action by dephosphorylating PKB. In the adipose tissue, insulin receptor expression was lower in HEP bulls, associated with higher concentration of hexosylceramide, which reduces the abundance of functional insulin receptors. Our findings confirm that diet-induced metabolic inflammation triggers ceramide accumulation and disturbs insulin signaling. As insulin insensitivity exacerbates metabolic inflammation, this self-reinforcing cycle could explain the deterioration of metabolic health apparent as chronic laminitis. By demonstrating molecular relationships between insulin signaling and sphingolipid metabolism in three major tissues, our data extend our mechanistic understanding of the role of ceramides in diet-induced metabolic inflammation.
Endogenous mucosal phosphatases characterization in duodenum brush border membrane of laying hens
(2025) Hanauska, Anna; Sommerfeld, Vera; Schollenberger, Margit; Huber, Korinna; Rodehutscord, Markus
Chicken mucosal phosphatases can partially degrade phytate contained in the feed. Little is known about the characteristics and degradation products of such mucosal phosphatases and the effects of age and genetic strain of the chicken. The objective of this study was to characterize endogenous mucosal phosphatases of two laying hen strains fed diets with or without mineral phosphorus (P) before and after the onset of egg laying. Hens of the strains Lohmann Brown-classic (LB) and Lohmann LSL-classic (LSL) were sacrificed in weeks 19 and 24 of age after 4 weeks of feeding one of two diets with (P+) or without (P-) mineral P supplement. Mucosa of the duodenum was collected, and the brush border membrane (BBM) of enterocytes was enriched and used for phosphatase activity determination. Additionally, the BBM was used in a modified three-step in vitro assay to study the InsP6 degradation products. The results of both in vitro assays were not significantly affected by hen strain and diet. The activity of mucosal phosphatase in 19-week-old hens was, on average, 0.8 µmol Pi/g BBM protein/min lower than in 24-week-old hens (P < 0.002). Consistently, the InsP6 concentration in the incubation residue was significantly higher in 19-week-old hens than in 24-week-old hens (P < 0.001). In the incubation residue, the concentrations of Ins(1,2,3,4,5)P5, Ins(1,2,3,4,6)P5, and Ins(1,2,3,4)P4 were significantly lower (P ≤ 0.002), and those of InsP3 and InsP2 were significantly higher (P ≤ 0.027) when BBM of 24-week-old hens was used compared to 19-week-old hens. The InsP6 degradation products suggest the activity primarily of a 6- and secondarily of a 5-phytase in the duodenal mucosa. The consistent results from both in vitro assays provide a comprehensive characterization of these enzymes. Under the conditions of this study, small intestine calcium concentration appeared to influence mucosal enzyme activity more than dietary mineral P supplementation.

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