Scientific Opinion on the safety and efficacy of vitamin B6 (pyridoxine hydrochloride) as a feed additive for all animal species

One-Pot Preparation of Hydrophilic Polylactide Porous Scaffolds by Using Safe Solvent and Choline Taurinate Ionic Liquid

Polylactides (PLAs) are a class of polymers that are very appealing in biomedical applications due to their degradability in nontoxic products, tunable structural, and mechanical properties. However, they have some drawbacks related to their high hydrophobicity, lack of functional groups able to graft bioactive molecules, and solubility in unsafe solvents. To circumvent these shortcomings, porous scaffolds for tissue engineering were prepared by vigorously mixing a solution of isotactic and atactic PLA in nontoxic ethyl acetate at 70 °C with a water solution of choline taurinate. The partial aminolysis of the polymer ester bonds by taurine -NH2 brought about the formation of PLA oligomers with surfactant activity that stabilized the water-in-oil emulsion. Upon drying, a negligible shrinking occurred, and mechanically stable porous scaffolds were obtained. By varying the polymer composition and choline taurinate concentration, it was possible to modulate the pore dimensions (30-50 µm) and mechanical properties (Young's moduli: 1-6 MPa) of the samples. Furthermore, the grafted choline taurinate made the surface of the PLA films hydrophilic, as observed by contact angle measurements (advancing contact angle: 76°; receding contact angle: 40°-13°). The preparation method was very simple because it was based on a one-pot mild reaction that did not require an additional purification step, as all the employed chemicals were nontoxic.

Assessment of a feed additive consisting of vitamin B6 (pyridoxine hydrochloride) for all animal species for the renewal of its authorisation (Kaesler Nutrition GmbH)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the assessment of the application for renewal of authorisation of vitamin B6 (pyridoxine hydrochloride) produced by chemical synthesis as a feed additive for all animal species. The applicant has provided data demonstrating that the additive in the market complies with the conditions of the authorisation. The FEEDAP Panel confirms that the use of pyridoxine hydrochloride under the current authorised conditions of use is safe for the target species, the consumers and the environment. Pyridoxine hydrochloride is non-irritant to skin and eyes. In the absence of data, no conclusion can be drawn on skin sensitisation potential. Pyridoxine hydrochloride may cause photosensitisation. Despite the lack of data on inhalation toxicity, the additive is not dusty and exposure through inhalation is unlikely. There is no need for assessing the efficacy of the additive in the context of the renewal of the authorisation.

Assessment of the application for renewal of authorisation of pyridoxine hydrochloride (vitamin B6) as a feed additive for all animal species

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the assessment of the application for renewal of authorisation of pyridoxine hydrochloride (vitamin B6) produced by chemical synthesis as a feed additive for all animal species. The applicant has provided data demonstrating that the additive in the market complies with the conditions of the authorisation. The FEEDAP Panel confirms that the use of pyridoxine hydrochloride under the current authorised conditions of use is safe for the target species, the consumers and the environment. Pyridoxine hydrochloride is non-irritant to skin and eyes and is not a skin sensitiser. It may cause photosensitisation. In the absence of inhalation toxicity studies, adverse effects in the respiratory tract cannot be fully excluded. There is no need for assessing the efficacy of the additive in the context of the renewal of the authorisation.

Nutrient stability in mould-infested feed and mitigating effect of dietary supplemental vitamins in brown laying hens

A 10-week study was conducted to assess the impact of mould infestation on nutrient stability of feed and the mitigating effect of supplemental tocopherol, retinol or a multivitamin on performance and hepatic histology of ISA Brown laying chickens. Two batches of corn were obtained: the aflasafe corn used in preparing control diet and corn with physical evidence of mould used in preparing diets 2 to 5 containing no supplemental vitamin, tocopherol, retinol or a branded multivitamin supplementations respectively. One hundred and fifty (150) laying chickens used were completely randomized into five dietary treatments with three replicates of 10 birds each. Results showed that there was gross instability in the nutrients of mouldy maize. The activities of the fungi depleted both protein and lipid contents by 11.54% and 12.72% respectively while crude fibre content rose by 31.7%. There was substantial drop in both retinol and tocopherol while aflatoxin content rose to 267 μg in mouldy corn and 118 μg in the mouldy diets. Feed intake was significantly (P < 0.05) reduced and consequently depressed (P < 0.05) egg production and feed efficiency. Egg quality differs (P < 0.05) in shell thickness and yolk colour. Proliferation of biliary duct epithelium, hepatic degeneration, cellular infiltration, hyper-cellularity or dilation of the sinusoidal spaces characterized livers of birds on mouldy corn diets while supplementation with vitamins subverted mycosis and aflatoxicosis as evidenced by normal-to-mild congestion of hepatocytes. It was concluded that mould contamination in feed compromised feed nutritive values, reduced bird performance and adversely impaired the liver of the experimental birds while tocopherol, retinol or a multivitamin supplementation relapses the damaging potential of mould and mycotoxin differently.

VITAMIN B6 (PYRIDOXINE HYDROCHLORIDE) TOXICOSIS IN FALCONS

This manuscript reports three independent accidental cases of vitamin (Vit) B6 toxicosis in gyrfalcons (Falco rusticolus) and peregrine falcons (Falco peregrinus) and a toxicology study that was conducted to characterize the clinical responses of gyrfalcons and gyrfalcon × peregrine falcons to a range of single intramuscular (IM) and oral (PO) doses of Vit B6. Both lethal and nonlethal doses were determined. Twelve female gyrfalcons died following IM injection of 1 ml of a vitamin B preparation. Within 30 min of injection, the birds passed pistachio green-colored urates and progressed to vomiting, anorexia, cessation of normal activity, ptosis, collapse, and death, occurring 24-36 hr post injections. Three individuals vomited frothy, partially digested blood and had clonic spasms and convulsions. Postmortem and histopathology revealed multifocal severe hepatic necrosis, splenic lymphoid tissue depletion and hemorrhages with arterial necrosis, and acute renal tubular necrosis. Following administration of a different, oral, mineral-vitamin supplement, a total of 21 peregrine falcons in two separate European facilities died suddenly. Histology of the liver showed diffuse congestion and multifocal coagulative necrosis with mild infiltration of heterophils. The particular nutritional supplement, used by both breeders, was analyzed and found to contain 5-9.7% Vit B6. Other randomly selected lots of the product contained 0.007-0.27% Vit B6. According to the product label, Vit B6 should have been present at 0.004%. To confirm the hypothesis that Vit B6 was responsible for the deaths of the falcons in Abu Dhabi, Vit B6 (British Pharmacopoeia [BP] grade) in powder form was diluted in water for injection and administered IM to four groups of falcons. Groups of four gyrfalcon × peregrine hybrid falcons or gyrfalcons (or both) were given a single IM dose of 5, 10, 15, or 20 mg/kg of Vit B6 or received an oral dose of 25, 50, or 75 mg of Vit B6. Only birds in the lowest-dose groups survived. The maximum nonlethal single doses of Vit B6 in falcons were 5 mg/kg i.m. and 25 mg/kg p.o.